338.272 Sci2

BRIEF DESCRIPTION OF THE

MINING, MATERIAL HANDLING,

PROCESSING AND ECONOMICS OF THE

WESTERN TAR SANDS PILOT PLANT PROJECT

Prepared by:

Bahrain Amirijafari, Ph.D. Science Applications, Inc. 1726 Cole"Blvd., Suite 350 Golden, Colorado 80401

December, 1981

TABLE OF CONTENTS

Section Page

1.0 INTRODUCTION 1-1

2.0 MINING 2-1

2.1 General 2-1

2.2 Geology 2-2

2.3 Exploration 2-4

2.4 Alternate Mining Concepts 2-6

2.5 Phase One Details 2-9

2.6 Mining Regulations 2-14

3.0 MATERIAL HANDLING 3-1

3.1 Transport from Minesite and Initial Screening 3-1

3.2 Primary Crushing 3-1

3.3 Secondary Crushing 3-1

3.4 Final Screening and Weighing 3-1

4.0 PROCESSING 4-1

4.1 General 4-1

4.2 Process Design Criteria .* 4-2

4.3 Process Description 4-7

5.0 ECONOMIC ANALYSIS 5-1

5.1 Introduction 5-1

5.2 Operating Cost 5-1

5.3 Effect of Bitumen Content on the Economics 5-12

5.4 Effect of Mining Cost on Total Operating Cost 5-12

APPENDIX A A- 1

LIST OF FIGURES AND TABLES

Figure Page

1.1 Location Map, Raven Ridge Project 1-2

2.1 Uinta-Duchesne River Formations 2-3

2.2 Typical Stratigraphic Record 2-5

2.3 Raven Ridge Exploration Program 2-7

3.1 Material Handling System Flow Sheet 3-3

3.2 Material Handling System Conveyor Elevations 3-4

4.1 Simplified Diagram of Western Tar Sands Pilot Plant. . 4- 9

4.2 Ultrasonic Solvent Ext. Process Flow Diagram 4-11

5.1 Profit Sensitivity 5-3

5.2 Percent Bitumen vs. Ton Mined/Bbl Product 5-13

Table

4.1 Estimated Feedstock Characteristics of the Tar Sands . 4- 5

4.2 Design Data and Process Performance Criteria 4-8

4.3 Storage Capacity of WTS Raven Ridge Pilot Plant. . . . 4-21

4.4 Utilities Capacities 4-27

4.5 Process System Utilities Requirements 4-29

5.1 Market, Financial and Tax Assumptions 5-2

5.2 Operating Cost Summary 5-4

5.3 Calculations of Various Operating Cost Elements. . . . 5-6

1.0 INTRODUCTION

Western Tar Sands, Inc. intend to construct a pilot plant for

extraction of bitumen from tar sands deposit in Raven Ridge, Utah. The

process consists of solvent extraction combined with an ultrasonic unit

to enhance recovery. This process is based on U. S. patents held by

Western Tar Sands. The process has also been patented in Canada and

other countries where there are substantial amounts of tar sands deposits.

Science Applications, Inc., the Golden, Colorado office, is

responsible for the conceptual design as well as supervision and manage­

ment of the engineering, procurement, and construction.

WTS/SAI's objective in construction of such a pilot plant is to

provide definite answers to many questions regarding the technical and

economic viability of a solvent extraction process in general. Even

though several bench scale models of various solvent extraction processes

have been built and tested, none of them provide answers to how the solvent

loss can be kept under control, what the operating cost of a commercial

plant will be, or the effect of bitumen content of the feed on the economic

success of the process.

The 30 barrels per day pilot plant, which is actually a mini-plant

(as will be described later) will provide many valuable answers. This plant

is to be built on WTS's Raven Ridge property located about 35 miles southeast

of Vernal, Utah, a mile off Hwy. 45, as shown in Figure 1.1. This plant is

designed such that it could be used* as a research and development tool in

order to determine the optimum operating conditions of a process, check out

the efficiency of operating units on an individual basis, and compare compet­

ing units by using them in parallel streams.

This plant will be operated for a minimum of a year in order to

determine the effects of seasonal climatic changes on the material handling

and processing systems. The plant will also be tested using different feed

stock; i.e., other Utah oil sands or material brought from Canada, Venezuela,

and Trinidad. Several solvents such as hexane, kerosene, qasoline, and

chlorinated solvents recommended by Dow Chemicals will be used.

In this report the mining, material handling, and especially the

processing systems will be described in some detail.

1-1

I D A H O

Q

> UJ

W Y O M I N G

us-6 Price

US-40^ Bonanza*

US-45

U T A H

A R I Z O N A

LOCATION MAP RAVEN RIDGE PROJECT

FIGURE 1.1

1-2

2.0 MINING

2.1 GENERAL

The main objectives of this section are to evaluate the different

methods by which the Raven Ridge area tar sands can be mined, select a best

method, and develop a reasonably detailed study of that method. Discussed

are the physical nature of the deposit, the recommended approach to each

project phase, and the goals of each phase.

For the purpose of providing a basis for these mining studies,

an arbitrary scaling up of annual tonnage requirements has been assumed as

shown in the following table:

Phase

One

Two

Three

Duration

Year 1 and 2

Year 3 through 5

Year 6 through 15

TPD Required

100

300-750

1,500

This increasing tonnage reflects reasonable scaling up that could

result from a successful pilot scale operation, improved plant performance,

longer production schedules, and increased plant size; also, additional ton­

nage may be required for other test,facilities in the area. However, this

report will be limited only to Phase One.

2.1.1 Phase One

Generally speaking, Phase One tonnage levels will be used to test

the ultrasonic/solvent extraction process. The mining operation will supply

adequate tonnage for an evaluation period of up to two years. Once the test­

ing data have been compiled and evaluated, decisions may be made to increase

the operating time and/or plant capacity and thereby move the project into

Phase Two.

Phase One's low tonnage requirements will present some problems

in transporting the material, storage, and reclamation. This problem will

be discussed in detail later and recommendations made.

2-1

There are adequate reserves for Phase One; however, Phases Two

and Three will require that additional Federal leases be acquired. Those

sections to the northwest should be considered and evaluated first. Those

sections to the southeast would come next.

2.2 GEOLOGY

2.2.1 General

The Raven Ridge Tar Sands Project is located within the geographic

boundaries of the Uintah Basin. The Basin's boundaries are specifically

defined as " the Uintah Basis is bounded on the west by the 111° 10'

meridian and on the east by about the 108° 25' meridian, on the north by

the 40° 30' parallel and on the south by the 39° 50' parallel." (See "Geo-

morphology of the Uintah Basin—A Brief Sketch" by Ray E. Marsell.)

The Raven Ridge Tar Sands Project coordinates are 109° 06' 15"

meridian and 40° 12' 30" parallel. The project currently lays entirely

within Utah State Lease ML 22168, Section 16, T7S, R25E, Salt Lake Base

and Meridian. (See Figure 2.1.)

2.2.2 Uintah Basin Geology, Tectonics, Structure and Physiography

Generally speaking, study of the Uintah Basin indicates the occur­

rence of considerable historic and tectonic geology.

The area's geologic history is characterized by the following:

" the history [of the Uintah Basin] includes first the accumulation of

continental Tertiary sediments both lacustrine (lake) and fluviatile (river,

stream), in a slowly subsiding basin with an aggregate thickness in excess

of 9,000 feet occupying an area of some 6,500 square miles."

It appears that a major tectonic event (the upthrust of the Uintah

block) occurred very near the geologic period of deposition of the Raven

Ridge Project tar sands. The resultant coarse clastic texture of the Duchesne

River Formation readily separates it from the older Green River Formation

(Figure 2.1). The uplifting continued for some time after deposition with

the present day structure dipping 24°-27° to the southwest.

The region offers interesting vistas of high plateaus, river val­

leys, and badlands topography. The exposure of outcrop rock varies from

2-2

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FIGURE 2 . 1 . UINTA-DUCHESNE RIVER FORMATIONS

2-3

horizontal or slightly dipping beds to massive upthrust with craggy outcrop

of near vertical strata.

2.2.3 Raven Ridge Tar Sands Project Site Geology and Structure

The site is located within Section 16, T7S, R25E, SLB&M. The

surface mine will start in the Si SWi NWi of Section 16 and proceed on

strike (S42°E). The Phase One surface mine will terminate at a point

that will allow for two years of process plant experimentation. The

mine site was chosen because of access and grade of tar sands.

The project site rests near the contact of the Duchesne River

Formation and the Green River Formation undivided (Figure 2.1).

Some ripple marks can be seen which give indication of wave action

from the northwest (out of the Uintah uplift region) but field work at this

time does not indicate channelization of the deposit in that direction.

The tar sand is a medium to fine grain sandstone and has some

bedding characteristics within the seam; no inter-bedded clay seams were

seen in the core samples or surface outcrop of the ore zone.

The overburden is largely fine to medium grained, thinly bedded

(6" to 12") sandstone inter-bedded with shale and some layers of clay. The

specific gravity of this material is 2.27 (by test). A typical stratigraphic

record is shown in Figure 2.2.

The seam of tar sand varies between 12' to 15' thick. Core drilling

has been performed to determine grade and overburden.

The tar sand sandstone has a specific gravity of 2.2 (by test)

which is expected to fluctuate slightly depending on the grade of the tar

sand.

As mentioned, field work indicates no major faulting at the sur­

face mine site. The beds are dipping at approximately 26° varying between

24° and 27° at S47°W.

2.3 EXPLORATION

The exploration program consisted of evaluating the outcrop

quality, surface, physical geology, and twin drilling with electric log­

ging at 14 sites.

2-4

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FIGURE 2.2.

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2-5

Location of the holes are shown on Figure 2.3. In addition to

the cores, bulk samples were taken from the poor, medium, and rich bitumen

content sand and analyzed. The results are summarized in Appendix A. A

revegetation plan, biological survey, and cultural resource inventory were

also carried out.

Information gained from this program has been very significant,

and the proposed mine plans in this report are the direct product of the

exploration program. However, it should be understood that another program

will be needed before a detailed study can be made of Phases Two and Three.

Conclusions supplied by this program include the projected grade,

tar sand thickness, tar sand weight, and geologic characteristics of the deposit.

2.4 ALTERNATE MINING CONCEPTS

Several alternate methods for mining the tar sand zone were avail­

able for consideration. However, the orientation of the tar sands zone in

regards to the steeply dipping strata eliminates some of those methods

immediately.

The dip ranges from 24° to 27° throughout the property but averages

26° in the Phase One surface mine area. This means that the dip is 1) too

flat to gravity stope, and 2) too steep to operate equipment in the normal

fashion without potential harm to the operator or equipment.

2.4.1 Underground Method

One solution offered requires the mining operation to be conducted

from underground during Phase One. This type of operation offers some bene­

fits. There would be less surface area disturbed, a higher grade of mill

feed could be maintained, and the actual mining process would require equip­

ment that would be better utilized for the small tonnage required.

The underground mine plan would be to drive two or three parallel

tunnels along the strike of the tar sands zone. A grade of 2-5% could be

engineered so that the higher grade material down dip could be included in

the mill feed.

The portal area would be at the outcrop near Drill Holes 2 and 9.

This area is better known as the "bulk sample site."

2-6

FIGURE 2.3

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WESTERN TAR SANDS.INC.

CORE & PILOT HOLES LOCATED IN

SECTION 16. T TS. R ZSE .SLBSU

UHTAH COUNTY. UTAH

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WESTERN TAR SANDS, INC RAVEN RlOGE EXPIXWATION PROGRAM

VERNAL, UTAH

The two or three tunnel systems would have heights of 8' and

widths of 12'; cross-cuts would be driven on 20' centers.

Short, near vertical sumps or stopes would be driven into the

left rib of the first left entry. At a point when the development mining

would be terminated, a second or retreat mining would split the pillars

and include another stope in the left rib of the first left entry, thus

increasing the recovery.

Underground mining presents several objectionable pitfalls that

relate to the Mine Safety Health Administration (MSHA) regulations for non-

metal underground mining versus the less stringent regulations for non-metal

surface mines.

There is also the probability that the underground mine would be

considered gaseous or explosive in nature which would increase the cost per

ton drastically because of the specially designed equipment that would be

required to operate in an explosive atmosphere.

Therefore, little consideration was given to underground mining

and it is recommended that the operation be a surface mining operation until

such time when overburden removal and other costs make surface mining un­

realistic.

2.4.2 Surface Mining

Several methods of surface mining are available to the project

for consideration:

2.4.2.1 Outcrop

This method allows the operator to quickly mine the outcrop with

a minimum of overburden being moved. The maximum depth of overburden would

be 10'. Objections develop in this particular method since the grade of

mill feed desired is 8%. Outcrop samples along the strike of the tar sands

zone indicate that the grade would be about 5.6% bitumen content.

2.4.2.2 Shallow Surface Mining

Shallow surface mining in this case means a maximum overburden

of 30-40 feet. This would allow the lower grade outcrop material to be

2-8

discarded as waste, stockpiled for further testing or comingled with the

higher grade material to maintain an average mill feed grade of 8 to 8.5%.

2.4.2.3 Deep Surface Mining

This method requires serious consideration when plant capacities

and grade requirements are such that large scale operations can be put into

effect. When large scale deep surface mining is taking place, overburden

of 100' to 150' or more could be expected. The actual pit configuration

would be dictated by the economics of that period.

2.4.3 Recommendations for Method of Mining

Generally speaking, because Phase One requires so little tonnage

per day (100 tons/day) and yet a fairly high grade mill feed, a combination

of outcrop and shallow surface mining methods should be used.

2.5 PHASE ONE - DETAILS

Approximately 0-30' of overburden will be removed to expose the

tar sands. As the overburden is being removed, a recovery trough will be

cut at the base of the tar sand zone. Entry into this recovery trough will

be via a decline of about 20% grade. Once the recovery trough is cut and

the overburden is removed, the exposed tar sands will be drilled by air

track mobile pneumatic drills and then blasted.

The detonation sequence wjll be such that the exposed tar sands

will be moved into the recovery trough so that a track-type loader will be

able to access the pulverized tar sand by traversing the decline. As the

ore is removed from the recovery trough, a track-type dozer will be used to

doze additional tar sand ore into the trough.

2.5.1 Explosives versus Rippability of Overburden

While developing this surface mine plan, two options have come to

light concerning the ways in which the overburden and the tar sands material

may be excavated. They are 1) shooting with explosives and 2) ripping the

overburden with a heavy dozer. The material appears to be thinly bedded,

2-9

anywhere from 8 inches to two feet. This makes it a good candidate for

ripping. Nevertheless, there is concern whether the oxidized portion of

the overburden is unconsolidated; as the operator cuts deeper, it is feared

that this sandstone will tighten and be substantially more difficult to rip.

A problem also exists with explosives in that when detonated, the

concussion may follow along the bedding planes, reducing the effect of the

explosives.

Nevertheless, it is recommended that explosives be used initially,

drilling and shooting the overburden and tar sands will allow a clean, cer­

tain beginning for the mine. Later, the operator can experiment with ripping

and a determination as to which process is more cost effective for this

specific site can be made.

Drillhole size for the explosives in the overburden removal phase

should be 3-3i inch. The 3£ inch hole is recommended so that larger pieces

will be available for the dozer to move.

In the tar sands removel, a 3£-4 inch shot hole diameter is recom­

mended so that the maximum amount of pulverization is accomplished on deto­

nation in order to reduce the workload at the process plant.

2.5.2 Sequence of Operation

The first step in the extraction sequence will be to drill the

overburden holes on 51 centers and spacing holes on 6' centers; the depths

of these holes will average about IS1 running from 4' to 5' near the out­

crop and 25' to 30' in the area of the recovery trough.

At the completion of these holes, they will be loaded with the

designated explosives and detonated.

The next step will be to move the overburden material into stock­

pile. Here again, the operator will use his own judgement in determining

the exact amount of overburden material to be placed in storage. Some

material will be moved up the incline and will be placed in another stockpile.

After the overburden and the incline material has been removed, the

actual mining of the tar sands can begin.

2-10

The detonation pattern will be according to a predesigned plan. It

should be noted that the shooting sequence will be such as to move the tar

sands to the recovery trough. Here, it can be loaded out by a track-type

loader, moved up the incline, and loaded into a truck where it is then

hauled to the mill site, crushed, and processed.

An on-site review of the preceding plan has been conducted in

order to assure the plan will work satisfactorily.

2.5.3 Dilution

One of the areas of concern encountered in a surface mine of this

nature is the problem of dilution. It is important that a mill feed grade

of about 8% is desired. In order to do this, the dilution must be limited

to 5-10% by weight; this presents a problem which is outlined below.

Dilution will enter into the mill feed material at five different

points in the transport system. If dilution at these points can be eliminated

or reduced, then the 5-10% dilution can be maintained. The five points are:

• Dilution Point 1: Removal of the overburden material. If the

barren overburden is allowed to comingle with the ore, dilution

rates will increase.

• Dilution Point 2: If the tar sand ore is removed from the sur­

face mine by dozer, the ore will become diluted when dozed up

the incline. There will be an opportunity for dilution to take

place as the ore moves across the barren overburden zone.

• Dilution Point 3: If the stockpiled ore is allowed to mix with

the surface in the stockpile area, dilution will take place.

• Dilution Point 4: If the seam is overdrilled or overshot below

the base of the tar sands seam, then dilution of the tar sands

ore from the barren underburden will occur.

• Dilution Point 5: When the recovery trough is excavated, there

may be considerable dilution of the ore material. The slot will

be cut at the foot of the incline parallel to the strike of the

tar sands. As this slot is being made, overburden material from

the highwall will possibly sluff into it diluting t/ie ore.

2-11

Appropriate solution or solutions have been found for each of

the above dilution points.

2.5.4 Equipment Description

Most of the equipment used in this mine plan is based on Cater­

pillar model numbers. The loader should be the 955 L-type track loader

which has a capacity rating at nominal heap of 2.25 loose cubic yards.

This loader can also be equipped with a light ripper-scarifier for testing

on its own capacity for ripping the tar sands or the overburden material.

The drill should be comparable to the AT 50 Air Track Drill Car­

rier which has an adjustable boom with a 33° rotation on the vertical axis,

and a vertical boom that has the ability to drill at any vertical angle. The

air compressor should be a Flexair 750 Portable Air Compressor or equivalent

which provides 750 cubic feet at 60 - 150 psig. Sullair also provides a

suitable machine called the Sulatrack which is a 750 A Track Drill. Either

of these drills will drill the 3-4 inch holes needed for the explosive.

The track-type dozer recommended for this job is the D8K with a

ripper.

2.5.5 Projected Tonnages

The chart below indicates the projected tonnages for the surface

mine (first lift) and is based on the pre-designed mine configuration.

Type of Material

Overburden

"Outcrop"

Decline

Mill Feed (Ore)

In Place (BCY)

5,860

925

660

3,875

Specific Gravity

2.3

2.2

2.3

2.2

Weight (Tons)

11,350

1,710

1,729

7,180

Broken (LYC)

9,000

1,400

1,000

6,000

The 7,180 tons of mill feed is approximately double the required

3,380 tons for the first three months of plant operation.

The additional tonnage is caused by three factors: 1) economics;

it is less expensive to mine more tons, 2) the increased width of the mine

2-12

because of the topographic nature of the deposit, and 3) the extra material

to the northwest of the initial starting plane. The actual grade of this

extra material is unknown and may be slightly weathered; however, it has

been included in the 7,180 tons of reserves of the first lift. A decision

on whether to actually include it as mill feed will be made once the over­

burden has been removed.

In conclusion, volume and tonnage calculations indicate there are

more than adequate reserves in this first lift for the first three months

of operation. A second lift will then be started to the southeast.

2.5.6 Operating Cost

Estimated costs for the first lift (7,180 tons tar sand ore) have

been calculated. Usage schedules are also determined. Estimates are based

on certain assumptions. Note that three tasks are described:

Job No. 001 Mine Site to Ore Stockpile

Job No. 002 Tailings to Mine Site

Job No. 003 Reclamation

• Mine Site to Ore Stockpile: This job requires that the overburden

be removed and the ore placed on the mill feed stockpile.

• Tailings to Mine Site: The tailings will be accumulating on a

daily basis at a rate that does not justify the 100% availability

of a truck and loader. The ore will therefore be accumulated in

lots from 1,000 to 3,000 cubic yards; then the contractor will be

notified to report to the plant site and remove the tailings to

the mine site.

• Reclamation: Final reclamation will take place at the end of the

project but replacement of the overburden and tailings as well as

forming of the final contour will be conducted concurrently with

mining extraction.

It should be noted that mining cost is estimated to be $6.67/ton

of tar sand, tailings handling costs are $1.25/ton and reclamation costs

are $2.25/ton for a total cost of $10.17/ton of tar sand. This high unit

cost is due primarily to inefficient use of necessarily large equipment in

conjunction with small tar sands tonnage requirements.

2-13

In addition, this estimate has been made based on the assumed

need to drill and shoot al_l_ overburden and tar sands. However, it is still

felt that the tar sands may be ripped by a dozer especially as the grade

improves with depth. Ripping will be attempted, and should it be effective,

cost savings will result through considerably reduced drilling and shooting.

Thus, appreciably reduced costs may be expected in large scale

operations in which 1) equipment capabilities may be fully utilized, and

2) ripping of the tar sands is practical. It is roughly estimated that

cost reductions on the order of 30% to 60% may be possible in operations

of 1,000 to 2,000 ton per day scale and working in reasonably favorable

conditions.

2.6 MINING REGULATIONS

A meeting was held with Federal Mine Safety and Health Administra­

tion (MSHA) personnel in June 1981. Details of the meeting are available.

Of immediate importance are: MSHA will have jurisdiction over the

mine and plant, notification prior to construction is required, and the use

of contractors for mining will negate the need for a training plan.

2-14

3.0 MATERIAL HANDLING

3.1 TRANSPORT FROM MINESITE AND INITIAL SCREENING

Tar sands will be transported from the mine site, either directly

from the mine or from a stockpile located near the mine, to the material

handling area by truck. The ore will be dumped onto a grizzly (large screen)

where material of size less than 6" x 6" will pass into a twenty ton hopper.

The hopper acts as a reservoir for the ore so that it may be discharged at a

controlled rate. Material that does not pass the grizzly will be forced

through using the front end loader or removed.

The material in the hopper will be fed onto a syntron vibrating

pan feeder to control the flow of material onto a conveyor where it will

be transported to the crushing unit. (See Figures 3.1 and 3.2.)

3.2 PRIMARY CRUSHING

Ore will pass from the conveyor into a Hazemag SAP-1 Impact Crusher

where the 6" x 6" material will be reduced to approximately li" x H" size.

The material leaving the crusher will be conveyed to a stockpile for future

use. (See Figures 3.1 and 3.2.)

3.3 SECONDARY CRUSHING

The secondary crushing phase will reduce the 1£" material from the

primary crushing to whatever smaller'size is required by the plant. Ore

will be taken from the primary crushing stockpile by front end loader and

once again be placed into the hopper. The ore will pass over the pan feeder

and onto the conveyor transported to the same crusher used for primary

crushing, however, operating at a different speed to achieve the required

smaller size. From the secondary crushing the ore will feed onto another

conveyor for screening. (See Figures 3.1 and 3.2.)

3.4 FINAL SCREENING AND WEIGHING

Material from secondary crushing will be screened to ensure that

all material does in fact meet the requirements of the plant in terms of

3-1

size. Material which does not pass the screen will be conveyed to another

stockpile and once again be cycled through secondary crushing (see Section

3.3). The material which does pass the screening will be weighed on a

Ramsey weigh belt feeder, then fed onto a final conveyor to be transported

to the processing plant. The tar sands are delivered to the extraction pro­

cess at a nominal rate of 100 lb/min. at ambient conditions. The current

operational mining philosophy is to use two operators during the mining

operation, stockpiling enough feedstock for one week of continuous processing.

(See Figures 3.1 and 3.2.)

3-2

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FIGURE 3 .2 . MATERIAL HANDLING SYSTEM CONVEYOR ELEVATIONS

4.0 PROCESSING

4.1 GENERAL

The recovery of bitumen from tar sands can be categorized as

either a thermal or a solvent extraction process. The Western Tar Sands

Raven Ridge Pilot Plant is a unique process plant, which incorporates a

counter-current three stage solvent extraction process with a patented

ultrasonic extraction process.

The patent awarded to WTS asserts that the ultrasonic extraction

unit will increase the rate of bitumen extraction from tar sand feed stock

in a solvent extraction circuit. This unique process provokes a number of

economic and process-design questions. These questions will be discussed

later. It is expected that the WTS Pilot Plant will clarify all problems

and question by meeting the following objectives:

• To test the extractive efficiency of the ultrasonic unit varying

the following parameters:

- Different tar sand feedstocks

- Solvent type

- Particle size of the feedstock

- Residence time

- Solids weight fraction in the slurry

- Ultrasonic power input

- Temperature

- Pressure

• Under steady state conditions study the efficiency of each

process unit as a function of the above parameters.

• To provide a meaningful product inventory for bitumen analysis

including upgrading and combustion studies.

The process design criteria, including feedstock and solvent

characterizations, process design requirement, and the test objectives are

discussed in the next section. The process is described in some detail and it

4-1

includes extraction (including the ultrasonic unit), solvent recovery,

storage, process control, data acquisition, and utilities.

4.2 PROCESS DESIGN CRITERIA

The process was designed on the basis of the following criteria:

• Test objectives

• Characteristics of the feed

• Other design data

4.2.1 Test Objectives

The WTS Raven Ridge Pilot Plant has been designed to achieve the

following test objectives:

1) Process different tar sand feedstocks on a "steady state" basis

to provide a meaningful product inventory for

a) Analysis

- distillation

- chemical composition

- particulate content

- heavy metal content

b) Upgrading to a finished product (i.e., diesel fuel)

c) Combustions studies (e.g., fluidized bed, boiler, etc.)

2) Vary significant process parameters in a controlled manner to

determine the effect on product quality, processing rate, and overall

energy consumption. Parameters that will be varied include:

a) Feedstock particle size: Smaller particles require more

energy for the crushing operation and may result in a higher particulate

content in the final product as well as more dust control problems in the

material handling/reclamation stages.

The system has been designed to handle particles from i" down to

10-28 mesh. It is recognized that the extraction ratio will be poorer for

the consolidated resources but may not suffer appreciably for the soft

4-2

unconsolidated oil sands. A matrix of recovery efficiency can be constructed

for each basic type of resource tested.

b) Ultrasonic energy input: The amount of ultrasonic energy added

to the slurry will be varied as will the residence time of the material in

the ultrasonic extractor. Power levels of at least five watts per cm2 should

be used to ensure intense cavitation. Insufficient power levels will not in­

duce local cavitation and ensuing bubble collapse on the particle surface.

c) Feedstock/slurry temperatures: Tests will be conducted with

different feedstock from various Utah deposits and material shipped in from

other resources and slurry line temperatures.

Higher temperatures increase the molecular motion of the solvent

and possibly its effectiveness. Also higher temperatures should decrease

the viscosity of the slurry, making it easier to mechanically agitate and

pump through the lines. Handling the product at elevated temperatures may

require less diluent and solvent to be left in the end product. Running

the process with different slurry temperatures will also provide some use­

ful information on the effects of climatic changes.

d) Mechanical mixing rates/speeds: Mixers are designed so that

the paddle speed can be varied to compensate for different particle sizes

and their associated settling rates. Although there may be some mechani­

cal scouring or local cavitation at the paddle surface that would enhance

the solvent extraction process, the primary effect of mixing appears to be

the creation of a turbulent, highly<onvective local environment surround­

ing each sand particle; a local environment that is not diffusion limited.

The power consumed by the mechanical mixers will be monitored as

well as the speed to be able to calculate the overall plant energy efficiency.

e) Slurry composition: The solids fraction in the slurry will

be varied ±20% about the baseline value to determine the effect on extrac­

tion efficiency and pumping/mixing requirements.

f) Slurry flowrates: Pumping equipment and control valves have

been designed to vary flowrates by at least ±50% to provide some data on

the sensitivity of residence time within the extractor units. Bypass lines

will be employed to circumvent particular extraction stages and thereby ob­

tain information on the effectiveness of that unit.

4-3

g) Type of solvent: The baseline solvent is hexane but casing

head gas, heptane, kerosene, and chlorinated solvents are also alternate

solvents that will be used. The use of added chemicals that could enhance

the extraction or solvent recovery process (i.e., wetting agents, pH modi­

fiers, etc.) may be employed.

3) Collect sufficient data so that a material and energy balance

can be determined for each major subsystem as well as the mining/process­

ing plant as a whole.

A detailed chemical analysis of the feedstock, the product extract,

and the processed sand/solvent residue will be required. It will require

monitoring power and fuel consumption levels during the operation. Based

on experience with other solvent extraction techniques, the economics of

the process will depend on the ability to recover the solvent from the pro­

cessed sand. As a result, this subsystem has been designed using proper

instrumentation and control to determine parameters which maximize the re­

covery process.

4.2.2 Characteristics of the Feed

The Raven Ridge deposit is a consolidated deposit with a bitumen

content of approximately eight percent. The water content is approximately

.10 percent by weight, which is unusually low for tar sands. The estimated

feedstock characteristics used in the design of the pilot plant are shown

in Table 4.1. One of the objectives of the pilot study is to produce a sub-

stantial amount of material in order to fully characterize the feedstock.

The information to be obtained from the characterization includes:

• Degree of consolidation of the resource

• Bitumen content

• Water content

• Size distribution, primarily the quantity of fines produced in the process

• ASTM boiling point curve

• Fire point of the bitumen

4-4

TABLE 4.1. ESTIMATED FEEDSTOCK CHARACTERISTICS OF THE TAR SANDS

6.5 ± 2 percent bitumen

135 lb/ft3 (estimate)

10 mesh to i" diameter

Bitumen analysis

Carbon 78.0 ± 2%

Hydrogen 9.5 ± 1%

Oxygen 6.0 ± 1.5%

Nitrogen 1.2 + 0.2%

Sulfur 0.4 ± 0.1%

Heavy Metals TBD

4-5

• Flash point of the bitumen

• Softening point of the bitumen

• Pour point of the bitumen

• Viscosity of the bitumen

• Heat capacity of the bitumen

• Specific gravity of tar sands in the bitumen

• Elemental analysis of the bitumen

• PONA analysis of the bitumen

• Bulk density of the feedstock

• Porosity and permeability of the feedstock

• Thermal conductivity of the feedstock

• Mineral content of the sands

4.2.3 Solvent Characteristics

The baseline solvent to be used is n-hexane: alternate solvents

include casing head gas, heptane, and kerosene. The use of surfactants,

pH modifiers, and chlorinated hydrocarbon solvents may also be employed.

In selecting a solvent, the following physical parameters are considered:

• ASTM Boiling Point Curve

• Vapor Pressure

• Heat of Vaporization

• Viscosity

• Heat Capacity

• Specific Gravity

• Kauri Butanol Value

• Molecular Weight

4-6

The following economic and design factors also enter into deter­

mining the best solvent:

• Economic

- Unit price

- Availability

- Deliverability

• Design

- Toxicity

- Lower and upper explosion limits

- Solvent losses in the product, spent sand and vapor

Another objective of the pilot plant study is to evaluate various

solvents from design and economic perspectives.

4.2.4 Design Data

The WTS Raven Ridge Pilot Plant has been designed for a nominal

tar sands processing rate of 100 Ib/min with a ±50 percent range of opera­

tion. For a bitumen content of eight percent and an estimated recovery

rate of 80 percent, the pilot plant is expected to yield 30 BPD of product

oil. The design data and process performance criteria are shown in Table

4.2.

4.3 PROCESS DESCRIPTION

The major process systems of the WTS ultrasonically enhanced

solvent extraction process are depicted in Figure 4.1. As indicated,

the process is comprised of the following major elements:

• Extraction

• Solvent recovery

• Storage

• Process control

• Utilities

4-7

TABLE 4.2. DESIGN DATA AND PROCESS PERFORMANCE CRITERIA

a) GENERAL DESIGN DATA

Location: Altitude: Plant Availability Factor: Climate: Product Storage: Fuel Storage Requirements: Solvent Storage Capacity: Plant Design Life:

b) MINING OPERATION

Mining Rate: Feedstock Size: Instrumentation:

c) PROCESSING OPERATION

Processing Rate: Product Character:

General Instrumentation Requirements:

d) ENVIRONMENTAL REQUIREMENTS

Air Quality: Archaeological:

Reclamation:

e) SAFETY REQUIREMENTS

Fire Control:

Insurance:

Emergency Communication:

Operational Safety:

Raven Ridge, Utah, Section 16, T7S, R25E 5,800 - 5,900 feet 10-12 hours/day for testing Semi-arid 2 weeks 2 weeks 2 weeks 1 year

30 ton/day continuous plus 1 week stockpile 28 mesh to i" diameter crushed/screened feed Method of monitoring fuel/power consumption

- mining/transporting (dozers, trucks, etc.) - crushing/screening (power requirements/

thruput)

100 lb/min. nominal (basically unknown) 4:1 bitumen/solvent ratio (estimate) Product market: Upgrading requirements:

Provide instrumentation material balances for:

unknown unknown—diluent may be required for handling

to monitor heat and

- extraction system - solvent recovery from product *- solvent recovery from sand

See Permit Applications. Two cultural sites were found on the property (see Mining Permit). Adverse impact on site 42UN984 will require minigation plan. See Revegetation Plan.

Utilize spacing and barriers in lieu of large fire water suppression system. Limit insured items to difficult-to-replace, plant-unique items (e.g., ultrasonic unit). Remote location of site will require emergency evacuation plan. Consider fail-safe emergency shutdown control system.

4-8

I SUPPORT SYSTEMS

UTILITIES

PROCESS CONTROL

Extraction:

Ultrasonics

and

Solvent

Residual Vapor Losses

/\

<- Recycle

Liquid Vapor

* ~

<-

\]/ Product

->

->

Solvent

Solvent Recovery from Vapor

Liquid Solvent

Solvent Vapor

^Solvent Vapor

Solvent Recovery from

Product

l£ olvent Oil "7K

V. Ta i1ings ->

Solvent Recovery from

Tailings

• ^

Storage:

.Solvent

.Diluent

.Diesel Fuel

.Product Oil

Solvent Makeup .Diesel & Diluent

Product Oil

7K~

Solvent

Liquid Solvent

Tailings

Clean Sand

Product OjJ

Asphal tenets

->

Figure 4.1. Simplified Diagram of Western Tar Sands Pilot Plant

The design basis, assumptions, and process interactions will be

discussed for each major process system.

4.3.1 Extraction

The WTS Raven Ridge pilot plant incorporates an ultrasonic unit

with a three-stage counter-current solvent extraction process. The general

process dynamics are depicted in the process flow diagram of Figure 4.2.

The extraction process can be operated independently from the mining opera­

tions and the solvent recovery from the product oil system. This has been

achieved by stockpiling the feedstock and using an intermediate storage tank

for the pregnant liquor stream. If operational problems do occur in the

extraction system, either mining or solvent recovery operations can continue.

The extraction process is assumed to operate at both isobaric, and

isothermal conditions. The extraction process is comprised of premixer,

ultrasonic system operating on the raw tar sands slurry, followed by the

counter-current solvent extraction circuit. The details of these units

are given below.

4.3.1.1 Premixer

The raw tar sands are transferred to a premixer through an airlock.

In the premixer, the mixing liquor and the raw tar sands are mixed to a nomi­

nal solids/liquid ratio of 1:1 to 1:4. The premixer is a rotating tank where

the slurry of tar sands and solvent can be rotated at various speeds. The

tar sands can also be mixed with the mixing liquor in a mixtank with an agi­

tator. It is the objective of this arrangement to compare the mixing effi­

ciencies of the premixer and the premixtank and agitator. One apparent

advantage to this coupled mixing arrangement is the added capability of

achieving the range of slurry composition required. The premixer will handle

the mixer solid functions with the mixtank and agitator offering a greater

efficiency of mixing with low solids fraction in the feed slurry. The pre­

mixer has been designed for a nominal flow of 6000 lb/hr of tar sands. The

solvent flow rate can vary from 3300 to 24,000 lb/hr in order to achieve

various solids to liquid ratio.

4-10

FIGURE 4.2

TM-I PREMIXER

HS-I ULTRASONIC

EXTRACTION UNIT

M-2 PRIMARY MIXER

M~4 SECONDARY

MIXERS

CY8TK-3 TAILINGS, CYCLONE,

THICKENER TRAIN

S-3 SEPARATOR

DRUM

HX-I SOLVENT/OIL

PREHEATER CY8TK-2

SECONDARY, CYCLONE THICKENER TRAIN

CN-2 CENTRIFUGE

CYftTK-l PRIMARY, CYCLONE

THICKENER TRAIN

M-6 TAILINGS MIXER

D-l TAILINGS ORYER

A-2 EXTRACT

OIL COOLER

HSANDS ED

A-l TAILINGS.VAPOR

COUoLNSER A-3

SOLVENT FLASH TRIM CONDENSER

1

HX-3 SOLVENT, FLASH

EXCHANGER

DD-I DEDUSTER

H08

s-i ASPHALTENE SEPARATOR

HOS

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® CM-T_^}—@-»[w\71 H V W j ® r

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STREAM NO

STREAM NAME

DESIGN Ib/W

SAND ib/hf

SOUD TAR tVW

UOUID TAR lfc/h,

SOLVENT IVtu

rEMPT/PRES PSA

STREAM NO

STREAM NAME

DESIGN lb/lv

HI TAR SAN03

6000

S520

460

A««.

w TAILINGS UNOERflfiW

7965

HI MIXED SLURRY

12602

5520

400

537

6145

120*F/12.0

3£ IEC

7965

HI MIXER FEED

12602

5520

346

591

6145

1 2 0 V 1 Z . 0

c w 2330

HI PREGNANT LIQUOR

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430

3461

1 2 0 V 1 2 . 0 .

Z3£I 6010

31 PRIMARY UNDERFLOW

8711

5520

173

334

2684

120- /12 .0

RECLAIM SOLVENT

233Q

HI RECLAIM LIQUOR

6444

62

6382

1 2 0 V 1 2 . 0

~w RECYCLE SOLVENT

5786

HI SECONDARY CY-2 FEED

15155

5520

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500

9066

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3E DILUENT

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HI MIXING LIQUOR

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457

6145

1 2 0 V 1 2 - 0 w EXTRACTED JBL

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HI SECONDARY UNDERFLOW

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2921

1 2 0 - / 1 2 . 0 s: 120V12.0

ASPHALTENES

la: RETURN SCV^EJUL

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~w RECOVERED SOLVXUI

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HI TAILINGS CY-3 FEED

14409

5520

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7«

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1 2 0 ' / 1 2 . 0

MAXE UP SOLVENT

70

T"1^ WESTERN TAR SANDS RAVEN RIDGE PILOT PLANT

DESCRIPTION ULTRASONIC SOLVENT EXT

PROCESS FLOW DIAGRAM WKJETTBT

MoAMcsff; B AMIRIJAFAPI

SAND IH/K. 5520 5520 5520 IBrT Basr-JtLX.

SOUD TAR ft/to 45 45 45 *9T acNTApraoMML

uamoTAft i»/w 14 14 14 421

SOLVENT I k / W 2306 2386 2330 56/375 KjO 2330 5777 14 3447

rcMP. T / P R E I P S U 12QVU.0 12Q-/12.0 157V11.0 100V12.0 120-/12.0 <M*/).?-0 eoyu.o 120»/12.0 120V12.Q B20*/i2.0

xmmx

70 """os-os-osz-soz Scfcnc* Application!, I W C J T M I scut m»a.«tt.DCHCc

4.3.1.3 The Counter-Current Solvent Extraction Circuit

A three stage counter-current solvent extract ion process is used.

N-Hexane is the baseline solvent. Alternate solvents including kerosene,

dr ip gas, surfactants, and chlorinated hydrocarbons are being considered.

Each extract ion stage in the c i r c u i t contains the fo l lowing iden­

t i ca l elements as depicted in Figure 4 .2 .

• Mixer

• Sump Pumps

• Cyclones

• Thickeners

Each item will be discussed as to its primary function, the process

assumptions made, and its relationship in the process flow of the circuit.

The function of the batch mixer in the circuit is to increase the

residence time, and the interfacial contact between the solvent and the tar

sand. The efficiency of each mixer is a function of the residence time and

the degree of agitation. The physical character of solvent/tar sands/slurry,

including the solids weight fraction, the particle size distribution, the

specific gravity of the mixture, and the slurry temperature, has a direct

bearing on the efficiency of the mixing cycle. Each mixer is constructed

with a draft tube as the outlet. This type of construction will prevent

short circuiting from occurring in the mixer, thus ensuring that the slurry

spends the full residence time in the mixer.

The mixed solvent/tar sands/slurry is gravity-fed to a sump pump.

The sump pumps in the solvent extraction circuit function as a mixer and as

a feed pump for the cyclones. The pumps in the circuit have been designed

with a high re-circulation rate; thus improving the solvent to solid contact

in addition to increasing the total residence time of the solvent circuit.

The cyclone-thickener trains, as depicted in Figure 4.2, selec­

tively separate the large particles and fines from the slurry. This step

is essential in the solid/liquid solvent extractions circuit for tar sands.

There are two cyclones in parallel in each extraction stage to adequately

cove" the range of solids to be experienced in the plant.

4-13

Efficient operation of the cyclones depends on the following

variables:

• Feed flow rate

• Feed pressure or pressure drop

• Solids concentration

• Solids size and shape

• Sol ids density

• Liquid density

• Liquid viscosity

• Back pressure

• Volume split

The efficiency of cyclones depends on the most critical design

parameter, i.e., the three aperature sizes for the feed, overflow, and

underflow. The cyclones in this process are designed such that they can

be varied to obtain the best operating conditions.

The overflow from the cyclones is delivered to the thickener

where the fines and the extracted oil/solvent mixtures experience a rela­

tively long residence time. A relatively high solids weight fraction in

the underflow will be experienced. The slurry is transferred by a diaphragm

pump located directly below the thickener.

It was assumed that a combined underflow of 60 to 70 percent

would be realized in the cyclone-thickener train.

4-14

4.3.2 Solvent Recovery

The recovery of solvent from the process streams is of primary

importance to the economic viability of the process. There are four sys­

tems where a potential for solvent loss exists. These systems are:

• Recovery of Solvent from the Product Oil

• Recovery of Solvent from the Tailings

• Vapor Recovery Circuit

• Drain System

Each of these systems is discussed in some detail.

4.3.2.1 Recovery of Solvent from the Product Oil

The product oil recovery system is based on an adiabatic equilibrium

flash separation of the solvent/oil solution. The product oil recovery cir­

cuit is composed of the following units:

• Solvent/oil preheater

• Flash heater

• Solvent flash exchanger

• Asphaltene separator

• Flash separator drum

• An extract oil cooler

• Solvent flash trim condenser

• Extract oil pump

The efficient operation of the flash recovery system is a function

of the solvent and oil composition and the operating temperature and pressure

of the flash drum. To determine the solvent/oil split the ASTM boiling point

curve for the solvent and the extract oil must be supplied. Pseudo and actual

hydrocarbon components can be determined from these curves, thus providing a

quantitative definition of the feedstock. From the solvent to oil ratio and

the component mixture, an overhead split can be calculated. The pressure of

the system is dictated by the pressure drop of the system downstream of the

4-15

flash separator and is constrained by the pressure rating of the flash

separator. The temperature of the system is limited by the hot oil system

which provides a maximum temperature of 600°F. The energy efficiency of the

flash system is dictated by the solvent type, the required solvent/oil split

and the efficiency of the exchanger units.

The solvent/oil split is limited or constrained by the minimum

amount of solvent required in the product to maintain fluidity until the

product stream is diluted with a diluent (kerosene). The amount of residual

solvent left in the extract oil is determined by the solvent type.

In the nominal design case, approximately 3891 lb/hr or 11.7 gpm

of pregnant liquor is delivered to the product oil recovery circuit. Approx­

imately 80 percent by weight is n-hexane and 11 percent by weight is extracted

oil. This extracted oil amounts to 90 percent of the feedstocks oil assay.

The solvent/oil solution is preheated from 120°F to 143°F by the solvent/oil

preheater, thus recovering some of the sensible heat in the extract oil.

The solution is then transferred to the asphaltene separator. The character­

istics and the quantity of asphaltenes are unknown since little has ever been

extracted from tar sands.

The solvent/oil mixture will reside in the asphaltene separator for

approximately 1£ hours. Due to the lack of knowledge concerning asphaltenes,

it is questionable whether they will separate out. If asphaltenes are present,

the higher temperature of 143°F will enhance the separation by reducing the

specific gravity of the solvent/oil solution.

The asphaltene separator can either be bypassed or the temperature

and the residence time can be increased by recycling the solvent/oil solu­

tion through the separator. This procedure will enhance separation of the

asphaltenes.

The solvent/oil solution is preheated to 245°F by the condensing

solvent, n-hexane, in the solvent flash exchanger, thus recovering the avail­

able latent heat of condensation of the solvent, 156 btu/lb in this case. To

achieve the design flash conditions of 32 psia and 391°F, approximately

1 x 10^ but/hr is input to the solvent/oil stream by a hot oil heater. An

adiabatic equilibrium flash occurs at the above conditions, producing an

8:1 solvent to oil split. It is assumed that a solvent content of 3.5 percent

4-16

by weight of the extract oil will be adequate to maintain fluidity of the

oil through the remaining process units. -7

As indicated in Figure 4.2, the extracted oil recovery rate

is 88 percent which is a 30 gpd production rate. The solvent loss in the

oil amounts to 20 percent of the makeup stream, or .24 percent of the cir­

culating solvent. The recovered solvent amounts to 3456 lb/hr, or 11.7 gpm.

This recovered solvent is reduced in temperature from 391°F to 120°F by the

condenser and the solvent flash trim condenser. It is returned to storage

at this temperature or directly mixed with the makeup stream and added to

the tailings mixer. Less than .1 percent of the oil is recycled with the

n-hexane solvent. These parameters will change with a change in the sol­

vent. As the range of the boiling point curve increases, as in the case

of kerosene, more oil will come off with the solvent in the flash system.

This is mainly due to the higher temperature at the flash stage.

4.3.2.2 Recovery of Solvent from the Tailings

The tailings recovery and treatment system is based on the process

of drying by heating the sand to a temperature above the boiling point of

the solvent. The efficient recovery of the solvent from the tailings is

achieved by the following units:

• Centrifuge

• Tailings dryer

• Tailings vapor condenser *

• Separator drum

• Pump

• Deduster

The tailings recovery circuit functions to substantially reduce

the residual solvent in the tailing and recover the solvent. This step

is of both economic and environmental concern.

To effectively reduce the amount of thermal energy required for

the drying step, a centrifuge was added to the recovery circuit. The cen­

trifuge reduces the amount of residual solvent in the tailing. The optimum

4-17

size of the centrifuge is determined by the economic balance between

centrifugal power input, capital and operating cost, and the capital

and energy requirements of the dryer. A small centrifuge with a capacity

of 6 to 8 gpm has been specified for the plant. This flow amounts to 50-

70 percent of the nominal flow delivered to the tailings circuit. The

liquid extract from the centrifuge is combined with the overflow from the

thickeners.

In the present process flow estimate, 7961 lb/hr of underflow from

the tailing-cyclone-thickener train is delivered to the tailing dryer through

the tailing dryer inlet airlock. The airlock functions to prevent backflow

of the solvent vapor into the slopes. The sand dryer is a Bethlehem unit

which consists of hollow screw feeder and a jacket. The hot oil flows

through the hollow screw and the jacket, thus providing heat to the sand­

wiched sand in between. The tailing dryer efficiency is a function of the

heat transfer coefficient between the slurry, the shell, and screw of the

dryer. The heating medium for the dryer is therminoil, which is supplied

to the dryer at a temperature of 600°F. The tailing dryer is rated at

660,000 Btu/hr. In the nominal design case, approximately 420,000 Btu/hr

will be required. This energy requirement assumes the centrifuge is not

operating.

The solvent is vaporized from the tailings at a temperature of

157°F and immediately condensed in the tailings vapor condenser at a rate

of 2330 lb/hr. This reclaimed solvent is mixed with the recovered solvent

to ultimately be recycled to the soTvent extraction circuit. The tailing,

exiting the dryer at a temperature of 157°F, has a residual solvent content

of approximately .1 percent, and a residual tar content of approximately 1

percent.

Depending on the fines produced during the processing, dust may

occur when the tailings are discharged. To prevent this from occurring,

for environmental reasons, process water will be sprayed on the tailing

prior to entering the discharge conveyor which is called the deduster.

To prevent the occurrences of dust, about 375 lb/hr of water may

be required. The actual process water requirements, if any for this step,

will be quantified during the pilot plant operation. The spent tailings

4-18

are hauled by a front end loader to the disposal area. A two to three hour

period for transferring the tailings by a front end loader is anticipated

at the nominal tailings flow rate of 6010 Ib/hr.

4.3.2.3 Vapor Recovery Circuit

The process systems of extractions, product oil recovery, tailings

recovery, the drain system, the storage system, and the hot oil system, will

experience solvent and light hydrocarbon losses. These losses occur from

the nitrogen blanket and purging systems which encompass nearly every process

unit and storage tank in the pilot plant.

The major solvent losses will occur in the premixer and tailing

dryer air locks and the Bethlehem seals. The loss is estimated to be approx­

imately 140 lb/hr. Other anticipated losses amounting to 40 lb/hr will be

from the blanketing system.

To reduce these losses to an economical and environmentally accept­

able level, a refrigeration vapor recovery system has been specified. The

solvent recovered from the vapor will be recycled and returned to the tailings

mixer or the solvent storage tanks.

4.3.2.4 Drain System

During the operation of the WTS pilot plant, spills, leaks and

malfunctions will occur causing solvent to be lost if they are not antici­

pated. These losses are minimized by a drain recovery system.

All leaks, spills and solvent dumps which may occur for whatever

reason will end up in the drain system. The solvent and the sands will be

pumped from the sump to the wash tank (tailing mixer). This system is also

under a blanket of nitrogen gas; consequently, some vapors will end up in

the vapor recovery system.

4.3.3 Storage System

The pilot plant contains eight major storage systems which include

the following:

4-19

• Solvent Storage

• Extract Product Oil Storage

• Diluent Storage

• Diesel Fuel Storage

t Asphaltene Storage

t Process Water Storage

t Nitrogen Storage

t Pregnant Liquor Tank

Each storage tank is maintained under a nitrogen blanket of 10 to

20 inches of water. The nitrogen blanket functions to reduce vapor losses

and allow the installation of a cheaper fixed roof API tank versus that of

floating roof type. Since the nitrogen blanket will become saturated with

solvent vapor, cross contamination between the storage tanks containing sol­

vent, product, asphaltenes, diluent, and diesel could occur. This has been

prevented by installing check valves on the supply header between the various

critical tanks.

Also as the nitrogen blanket becomes saturated with the solvent,

the saturated mixture will eventually reach the exhaust header which is

either vented or recycled through the refrigerations vapor recovery system.

All storage tanks for the pilot plant have been specified as 220 Bbl API

tanks rated at 5 psig. The number of tanks for each system and the storage

capacity at the nominal design case is indicated in Table 4.3.

4.3.4 Process Control

The WTS pilot plant is superimposed with a versatile process control

system and an extensive data acquisitions grid. The control system has been

designed to operate the following process systems as separate systems or as

a complete process unit.

t Extraction

• Solvent Recovery

• Storage and Vapor Recovery

4-20

TABLE 4.3. STORAGE CAPACITY OF WESTERN TAR SANDS

RAVEN RIDGE PILOT PLANT

Storage System

Solvent

Product

Diluent

Diesel

Asphaltenes

Process Water

Pregnant Liquor

Nitrogen Blanket

No. of Tanks (Future Plan)

2

2 (4)

2 (3)

Actual Storage Capacity (Bbl) (Future Total)

410

420 (840)

420 (630)

420

420

5000 gal.

210

500 gal.

Process Storage* (Days)

53

6 (12)

9 (14)

7

1

1 - Based on nominal flow case, continuous 24 hour operation per day.

Due to the high pour point of the product oil and the asphaltenes, electric

bayonet heaters were specified for the product oil and asphaltenes storage

tanks.

4-21

The specific control options and the general guidelines for each

system will be discussed. The primary function of the process control system

is to bring the pilot plant to a steady state operation and to dampen the

minor process perturbations which occur during normal operations of any plant.

The pilot plant has been designed with an extensive interlocking

control system. This system functions primarily to allow for the smooth

transition during startup and shutdown operations. The prerequisite logic

matrix which dictates the sequential shutdown and startup prevent the over­

loading of any single unit; thus, preventing spills, undue shutdowns, and

startup problems. As well as remote automatic control through the inter­

locking system, local on/off control is included for each unit, as well as a

control/indicator panel which indicates the operational status of each unit.

The capability of knowing the operational status of each unit via the control

indicating panel as well as the ability to locally shut down a specific item

enhance the operation and safety of the pilot plant. Two remote energency

shutdown switches which shut the system down are strategically located. One

is in the control room and the other is located in the plant. By throwing the

switch, the complete plant with the exception of the mixer agitation and

rakes in the thickeners will shut down.

Each system is automatically controlled by the primary process

variable, whether it be temperature, pressure or flow. The extraction sys­

tem, to be discussed next, is the most complex control circuit in the plant.

The malfunction or failure of any process unit will initiate an

alarm and flashing light. This will require the immediate response of the

operators. In some cases, due to the interlocking controls of the plant,

the system may begin to sequentially shut down, whereas in other cases, only

the local attention and response of the operator is required.

4.3.4.1 Extraction Control Circuit

The extraction circuit is probably the most complex system to

control due to recycle streams, and the amount of interlocking which must

be done to prevent major operational upsets.

It is the objective of the control circuit to maintain an isothermal,

isobaric and steady state operation of the counter-current extraction process.

4-22

The extraction system is inherently interlocked with the tailing

recovery, and the raw tar sands conveyor systems. The temperature of the

extraction process is dictated more specifically by the temperature of the

recovered solvent, the raw tar sands, and the ambient temperatures. The

pressure of the system is dictated by the vapor pressure of the solvent and

the operation or interaction of the nitrogen blanketing system with the

extraction system.

The operation of the extraction circuit is not interlocked with the

operation of the product recovery circuit; though if the product recovery sys­

tem is not functional, the temperature capabilities of the plant are solely

limited to ambient conditions.

Flow rate, the primary control variable in the solvent extraction

circuit is maintained by variable speed pumps rather than control valves.

Due to the high percent of solids in the process streams, erosion would be

a major problem with control valves. The indication of flow for the various

process streams is accomplished by sonic, orifice, turbine, or rotameters,

depending on the characteristic of the process stream, onic meters are used

on all slurry flows, and turbine meters are used primarily on solvent/oil

streams.

Referring back to Figure 4.2, the solids content of the mixed

slurry is determined by setting the solids to mixing liquor flow ratio.

The solids feedstock flow rate is locally set at the feed hopper. By set­

ting the above ratio the mixing liqujor flow rate is controlled by the mixing

liquor variable speed sump pump. The total flow rate as well as the solids/

liquid ratio is translated throughout the complete extraction circuit,

through the various flow and level indicator-control circuits.

Startup and shutdown are critical to the operation of the plant.

To allow for the smooth transition between the operation and the startup

and shutdown modes, an interlocking control matrix has been designed.

Either one or a number of the following prerequisites are required to

initiate a shutdown of the solvent extraction circuit:

• Failure of the tailing dryer

• Failure of the tailing deduster

4-23

• Failure of any pump in the extraction circuit

• Failure of the thickeners

• Failure of rotary airlock in the dryer

• Failure of any diaphragms pump

To start up the extraction circuit, the following prerequisites

are required:

• Generator be running

• Nitrogen blanket and purge system be running

• Hot oil system be running

• Instrument air system is operational

• Mixers and thickeners are started

• Tailings deduster and dryer are running

• Control systems are operational

When the above prerequisites have been met, startup of the extrac­

tion system can proceed. Startup of the extraction process involves the

sequential startup of the various pumps in the circuit. The startup order

is given below:

• Primary cyclone feed pump

• Secondary cyclone feed pump

• Tailings cyclone feed pump"

• Reclaim liquor pump

• Feed pump

• Mixing liquor pump

• Pregnant liquor pump

• Solvent pump

• Thickener diaphragms pump

4-24

4.3.4.2 Solvent Recovery from the Product Oil

As previously stated, the primary operation of this system is the

adiabatic flash separation of the solvent from the extract oil. To achieve

the smooth operation of the systems; temperature, pressures, and flows are

controlled. Levels are maintained in the various separators to maintain

the necessary NPSH for the various pumps.

The pregnant liquor flow rate is set by the solvent recovery feed

pump. This flow rate is independent of extraction circuit as long as the

storage capacity of the pregnant liquor tank is not exceeded. Approximately

only one day of storage of pregnant liquor is available which indicates that if

at all possible,it is imperative that the solvent extraction circuit be

operational. The critical control parameters in this circuit include the

pressure of flash separator and the temperature of solvent/oil feed to the

flash separator. By controlling these two parameters, the product oil to

solvent split can be controlled. The temperature of the system is limited

by either the vapor pressure of the solvent or the flash tank pressure

rating, whichever comes first. The flash tank pressure rating is 150 psi

which is more than adequate for the temperatures and solvents being studied.

4.3.4.3 Storage and Vapor Recovery

The storage system is controlled by the following parameters;

temperature, pressure, and level. The temperature of the product oil and

asphaltene storage tanks is maintained above the pour point of the compo-

nents. The pressure in the tank is maintained below the API rating of 5

psi by maintaining an open system. The level is monitored in each tank to

prevent spill during loading operations and to indicate when ordering of

solvents, diluents, or fuel and shipping of the product oil must occur.

The operation of the storage, vapor recovery and the nitrogen

blanket systems are interlocked. It is a prerequisite that the nitrogen

blanket system be operating prior to the operation of any system. The

function of the nitrogen blanket system in relation to the storage system

is primarily to maintain the concentration of solvent vapor in the vapor

space outside of the LEL to UEL, lower explosion to upper explosion limits,

and to reduce the solvent losses to the atmosphere.

4-25

The nitrogen blanket system in conjunction with the glycol seal

on the vent stack,prevent the influx of oxygen (air) into the system.

This substantially reduces the possibility of explosion.

Solvent losses from storage and other systems occur to the atmos­

phere through the vent stack. It is the function of the refrigeration vapor

recovery system to cut down these losses as much as possible for economic

and environmental reasons.

The vapor recovery system is connected in parallel to the vent

stack such that if an explosion or an unexpected flash or surge would occur

the nitrogen header piping is large enough to adequately handle the vapor,

and vent it through the stack without disrupting the vapor recovery system.

If high or low levels in the storage tanks occur both warning

lights and alarms will be activated. This will initiate the response of

the operators. This may necessitate the shutdown of the loading opera­

tions, a specific pump, or the pilot plant in more drastic circumstances.

In summary, the control and operation of the storage system is

relatively simple.

4.3.5 Utilities

The pilot plant is a self-contained system, supplying its own

electrical, heating, and water requirements. The capacities of the five

major utilities systems listed below are tabulated in Table 4.4.

• Electrical

• Process heat

• Process and Instrumental Air

• Nitrogen

• Process Water

The function of each system will be discussed in the following

section.

4-26

TABLE 4.4. UTILITIES CAPACITIES

System

Electrical

Main Generator

Emergency Generator

Heat: Hot Oil Heater

Process & Instrument Air

Nitrogen Supply

Process Water

Description

277/440V, 3, 4 W

120/20BV, 3, 4 W

200 SCFM @ 80 psig

500 gal. liquid N2 tank

5000 gal. potable water supply,'40 gpm @ 70 psig

Power

440 kW

50 kW

2 MM Btu/hr.

4-27

4.3.5.1 Electrical

Two diesel generators have been specified for the pilot plant.

The main 440 kW generator supplies the power for the entire pilot plant.

The function of the 50 kW emergency generator is to supply power

to the following units in case of an emergency shutdown of the main gener­

ator:

• Diesel pumps

• Water pumps

• Water heat tracing

• Lights

• Purge air fan

• Critical fail open solenoid valve

To maintain a reliable operation, two 1 gpm, 1/3 hp diesel pumps

are provided as a backup system for providing fuel to the generator.

The utility requirements of the various process systems are shown

in Table 4.5. These requirements were determined using maximum horsepower

ratings of the equipment. In this analysis, there was no attempt to account

for the system uses of nitrogen, instrument air or process water. As Table

4.5 indicates, the solvent recovery system requires nearly double the

electrical energy required by the extraction process. When the heat require-

ment of 2 MM Btu/hr is converted to kW we can see that the solvent recovery

circuits require 716 kW or 9 times more energy than the extraction process.

To reduce the energy requirements of the recovery system would greatly aid

in optimizing the design of a commercial tar sands extraction process.

4.3.5.2 Process Heat

Process heat is supplied by a Bethlehem hot oil heater rated at

2 MM Btu/hr. The primary function of the heater is to recover the solvent

from the extracted oil and the tailings. At a temperature of 600°F, therminoil

will degrade if it comes in contact with oxygen. A nitrogen blanket system

4-28

TABLE 4.5. PROCESS SYSTEM UTILITIES REQUIREMENTS

Process System

Mining and Material Handling

Extraction

Solvent Recovery

Storage

Utilities, Auxiliaries

TOTALS

Electrical

—

78.2

131.0

19.0

147.0

375.2 kW

Heat

—

—

2 MM Btu/hr. (585. kW)

—

-. — —

2 MM Btu/hr.

4-29

is provided to avoid this. At present, no actual estimates are available

on the degree of degradation. However, some makeup oil will be kept on hand.

4.3.5.3 Process and Instrument Air

A diesel driven air compressor supplying 200 SCFM at 80 psig has

been specified for the pilot plant. Approximately 100 SCFM will be dryed

to -40°F dewpoint which will prevent condensation and freezing from occurring

in the instruments.

4.3.5.4 Nitrogen

The nitrogen will be used to prevent influx of oxygen into the

solvent extraction system, the vapor recovery system, and the storage sys­

tem. To achieve these objectives, nitrogen is used as a blanket and a purge

gas. The nitrogen blanket system will consume about 13 lb/hr of nitrogen.

The purge system which operates on the airlocks and the premixer will con­

sume 27 lb/hr of nitrogen. Under normal design conditions, the total

nitrogen consumption is anticipated to be 40 lb/hr, or 60 gph. This trans­

lates into a 3 to 4 day supply of nitrogen using a 500 gallon liquid nitrogen

dewer. In this case, two dewers should be supplied, which would offer a

design capacity of one week.

4.3.5.5 Process Water

During normal operations, process water consumption is anticipated

to be quite low. For the present design, little if any water is anticipated

for wetting of the spent tar sand. This process parameter will be quantified

during the operation of the plant and could ultimately be of economic and

environmental significance. Other uses of water in the pilot plant are pri­

marily restricted to potable water, eye wash and safety shower use and

cleanup. For these various uses, a 40 gpm 70 psig pump is being supplied.

These are minimum estimates for the anticipated water consumption require­

ments.

4-30

5.0 ECONOMIC ANALYSIS

5.1 INTRODUCTION

This economic analysis projects a net profit of $5.43/barrel of

oil sold based on a capital investment of $5,000/daily barrel, an operat­

ing cost of $25/barrel (details of operating cost are given in Section 5.2),

an oil price of $35/barrel and a required rate of return on equity of 18

percent.

We assume the project to be financed entirely with equity funds.

The analysis is performed in constant dollars, assuming a washout of the

effects of cost and price escalation (the complete set of assumptions for

economic analysis are listed in Table 5.1)„

Project sensitivities to variations in capital cost, operating

cost, oil price and required rate of return have also been estimated and

are shown in Figure 5.1. As can be seen, the project is far more sensi­

tive to downside variation in operating cost and oil price than capital

cost or required rate of return. This effect is primarily due to the

short development schedule which allows positive returns by year three.

However, even with a longer development schedule, this relationship would

remain apparent, if less pronounced.

5.2 OPERATING COST

A summary of operating cost is given in Table 5.2. It shows the

costs of:

• Mining and Restoration

• Solvent Loss in Tailings

• Cost of Heat Input

• Cost of Power

• Cost of Labor and Maintenance

It should be noted that mining and restoration are used as operating

cost rather than capital investment.

5-1

TABLE 5.1. MARKET, FINANCIAL AND TAX ASSUMPTIONS

Item Assumption

FOB Selling price, Raw Shale Oil (1981)

Escalation in Oil Selling Price

Escalation in Operating Costs

Escapation in Capital Costs

By-product Sales Credits

Production Days per Year (stream days)

Required Rate of Return on Equity

Fraction of Investment Debt Financed

Working Capital as a Fraction of Peak Capital Expenditure

Startup Cost Allowance as a Fraction of Opeating Cost

Severance Taxes (Fraction of Gross Oil Revenues)

Property and Ad Valorem Taxes (Fraction of Revenue)

Depletion Allowance (Fraction of Gross Oil Revenues)

Depreciation

Federal Income Tax Rate

Utah Income Tax Rate

Investment Tax Credit

Energy Tax Credit

Tax Liability Treatment

Capital Investment ($/daily bbl)

Operating Cost ($/bbl)

Construction Period

Operating Life time (including construction)

Full Production

First Production

$35.00/bbl

None taken

350

18%

-0-

10%

15%

2%

2.5%

U%

1981 ACR System

46%

5%

10%

10%

Flow Through

$5,000

$25.00

2 years

25 years

Year 4

Year 3

5-2

FIGURE 5.1. PROFIT SENSITIVITY

5,000 10,000 15,000

CAPITAL COST ($/bbl/day)

$5.43/bbl @ $25/bbl

25 30

OPERATING COST ($/bbl)

8 T

6"

4--

2--

» — » -

$5.43/bbl @ $35/bbl

$5.43/bbl @ 18%

o

25 30 35

OIL PRICE ($/bbl)

40 18 20 25 30 REQUIRED RATE OF RETURN (%)

35

TABLE 5.2. OPERATING COST SUMMARY

Cost Element Dollar/Barrel Percent

Mining and Restoration

Solvent Loss

Heat Input

Power

Labor and Maintenance

Total Operating Cost per Barrel of Oil Production

9.40

3.00

8.00

2.20

1.20

23.80

39.60

12.60

33.60

9.20

5.00

100.00

5-4

5.2.1 Calculation of Various Operating Cost Elements

The assumptions involved in calculating the operating cost are

given in Table 5.3. As stated above, the various cost elements contribut­

ing to the operating cost are:

• Mining and Restoration

• Solvent Loss in Tailings

• Cost of Heat Input

• Cost of Power

• Cost of Labor and Maintenance

Details of each of these elements is listed in the following

outl ines.

5-5

TABLE 5.3. CALCULATION OF VARIOUS OPERATING COST ELEMENTS

Basis: Commercial Scale Plant Size 1000-2000 bbl/day (Optimum size to be determined later)

Mining and Restoration Cost: $3.50/ton

Solvent Cost: $1.40/gal (hexane), $1.10/gal (kerosene)

Electrical Power: $.03/KW-hr. (generated on site or purchased industrial rate)

Fuel Costs: S7.25/MM Btu (No. 2 fuel oil), $4.00/MM Btu Natural Gas)

Solvent Loss: 0.1 percent by weight in the tailings sand. 5 percent solvent in product (no operating cost, since the solvent will be as valuable as the product). 5 percent solvent in the asphaltene (Again, no loss assumed because it may be recovered at cost.)

Recovery: A recovery of 84 percent is assumed; i.e., if the feed contains 100 lbs. bitumen, 84 lbs. will be recovered as useful (marketable pro­duct), 16 lbs. will be lost in tailings and as asphaltenes, etc. which is considered not to have any value.

Labor and Maintenance: It is assumed that the 1000-2000 BPD plant will be operated and maintained by 7 persons (1 supervisor; i.e., plant manager, 4 operators, and 2 maintenance) at an average annual cost of $30,000 per person.

5-6

5.2.1.1 Mining and Restoration Costs

Amount of Oil Production:

100% Recovery

8 lbs, bitumen „ 100 lbs. v 1440 min. „ ft.3

100 tar sand A min. A 24 hr. day A 0.92 x 62.4 lb.

Assuming 84% Recovery

Oil Production = 0.84 x 35.77 ~ 30 PBD

Weight of Tar Sand to be Mined

Zero loss: wt. in tons/day

100 lbs. Y 1440 min. v ton _ -,0 *.nne/A*„ — ^ r z X A X or,nr, T , = 72 tons/day

mm . day 2000 lb. J

Assuming a 10% loss in fines, dust, unused rejects, etc.

Wt. in tons/day

72 x (1 + .1) = 80 tons/day

Tons Mined per Barrel of Oil Produced

80 tons/day ^ 30 ^- = 2.67 say 2.7 | ^ p

Mining and Material Handling Cost = $3.50/ton assumed

Mininq cost/bbl = - % ^ x 2.7 ^^- ~ $9.70/bbl ton DDI

5-7

5.2.1.2 Solvent Loss in Tailings

Amount of Tar Sand Processed = 72 tons/day

Tailing Sand = 72 X [l-(.08) x 0.9] = 67 tons/day

Solvent Loss Assumed to be 0.1% by weight

67 t°n x 200 lbs, sand „ 0.1 lb. solvent _ ..,. lbs.

day ton 100 lb. sand day

Solvent Density - 35.71 ||£j P 220°F

Gallons/day loss

lbs. v ft.3 134 X 35f71 lb X 7'4ft?31' ~ 28 9als/day S a y 30 G P D

day

Cost/gal lon of Hexane = $1.40

Cost of Solvent Loss = $1.40/gal . x 3 0 ^ ^ = $42.00

Cost of Solvent Loss _ $42.00 PD t l A n / h h l

bbl of product ~ 30 BPD " » 1 - W / D D I

Solvent Loss in Solvent Recovery System

No accurate estimate is avai lable at present. However, it is estimated that the solvent loss in the Solvent Recovery System w i l l be about $1.60/ bb l . If the cost was higher, it would pay to i n s t a l l a vapor recovery system.

Total Solvent Loss = $1.40 + $1.60 = $3.00/bbl

N0Tp- The solvent not recovered from the o i l product or the asphaltenes is assumed to sel l fo r the purchased pr ice .

5-8

5.2.1.3 Cost of Heat Input

The heat input occurs in

•1. Solvent Recovery from the sand

2. Solvent Recovery from the product

1. Heat Input to the Sand Amount of Heat Input = 750,000 Btu/hr.

2. Heat Input to the Solvent/Product System Amount of Heat Input = 1,250,000 Btu/hr.

Total Heat Input = 750,000 + 1,250,000 Btu/hr. = 2,000,000 Btu/hr.

Amount of fuel used to generate the heat required:

2,000,000-[^ X (1 + .25) = 2,500,000 Btu/hr. ̂ eat^oss) "%

Assuming cost of $4.00/MM Btu (natural gas)

Cost of Heat Input/Day:

2 , 5 0 0 , 0 0 0 ^ X ^ X M ^ ; f f 0 B t u - 5240.00/day

Cost of Heat/bbl of oil = ^ Q ' 0 0 = 8.00 S/bbl

5-9

5.2.1.4 Cost of Power

Total Power Requirement from P&IDs = 175 HP

Horsepower for the crusher = 25 HP

Total Power = 175 +25 = 200 HP

In a commercial plant only 60% of present horsepower would be utilized.

200 X TO = 12° HP

120 HP x 0.75 ~ ^ - = 90 KW-hr.

KW-hr Power used per day = 90 KW-hr. x 24 = 2160 N

day

Assuming a cost of $.03/KW-hr.:

2160 X | j j5 jL = $64.80/day

Power cost per bbl of Product

$64.80 30

= $2.16 Say $2.20/bbl

5-10

5.2.1.5 Cost of Labor and Maintenance

Assuming seven people at an average annual cost of $30,000/yr.

1 plant manager

4 operators

2 maintenance

7

7 x $30,000 = $210,000/yr.

Assuming a 330 stream day per year

Daily Cost = ^ j ^ " 0 0 = $636/day

Assuming a $1000 BPD commercial plant

Labor cost/bbl = $636/1000 = $0.64/bbl

Assuming a $.50/bbl for other maintenance costs

Total Labor and Maintenance per bbl: .

$0.64 + $0.50 = $1.14/bbl Say $1.20/bbl

5-11

5.3 EFFECT OF BITUMEN CONTENT ON THE ECONOMICS

As shown in Figure 5.2, the percent of bitumen content greatly

affects the tons of ore which should be mined in order to produce one barrel

of product. The amount of ore to be mined also depends on the percent of

bitumen recovery in the solvent extraction process and the specific gravity

of the product. These effects are also shown in Figure 5.2.

5.4 EFFECT OF MINING COST ON TOTAL OPERATING COST

As seen in Table 5.4, which shows the summary of operating cost,

the mining and restoration cost is the highest value. Therefore, the total

operating cost is very sensitive to the cost of mining.

The mining cost can very from 32 percent to 53 percent of the

total operating cost, depending on the dollars spent to mine one ton of

ore. Table 5.4 shows the mining costs varying from $2.50 per ton to $6.00

in 50<t increments. As a result, the mining cost as a percent of total

operating cost shows a variation from 31.8 percent to 52.8 percent.

The second most important cost element in the operating cost is

the cost of energy as heat input. As a result, a combined thermal/sol vent

extraction would make economic sense since the waste heat from the thermal

process can be used in the solvent extraction process. Such a combined

process has been developed by Science Applications and Western Tar Sands

and is in the process of being patented. Details of the combined process

could be made available upon request.

5-12

tkot HEWLETT 7/LM PACK An O

FIGURE 5.2.

WESTERN TAR SANDS PER CENT BITUMEN v« TONS MINEO/BBL PRODUCT

TONS ORE MINED/BBL PRODUCT (\j m v

LEGENDt SPECIFIC GRAVITY . 8 . 9 1

/-\ >-a: > o CJ UJ

a: en CO UJ u a oc o_ «

ca m

in z a

•* in <Q t«* s H N a) • * in

PER CENT BITUMEN(BY WT.)

100

>-a: UJ > a UJ

a: CO CO UJ CJ

a CL.

U l CJ

a: UJ Q-

TABLE 5.4. EFFECT OF MINING COST ON TOTAL OPERATING COST

Mining Cost Mining Cost ($/ton)

2.50

3.00

3.50

4.00

4.50

5.00

5.50

6.00

($/bbl)

6.71

8.06

9.40

10.74

12.09

13.43

14.77

16.11

1 Operating % Mining Cost of

t ($/bb1) Total Operating Cost

21.11 31.8

22.46 35.9

23.80 39.5

25.14 42.7

26.49 45.6

27.83 48.3

29.17 50.6

30.51 52.8

5-14

APPENDIX A

QUANTITATIVE ANALYTICAL RESULTS OF TAR SANDS

PROPERTIES AT RAVEN RIDGE

Laboratory analyses were conducted to determine the weight percentage of the included bitumen in various solvents, characterize the bitumen and to establish the rock particle size. The methods used include the following:

Soxhlet Extraction using Toluene,

Selected Soxhlet Extractions using Hexane and Chloroform,

Selected Residual Soxhlet Extractions using Pyridine,

Selected SARA (Saturates, Aromatics, Resins and Asphaltenes) Analyses,

Selected Ultimate (C,H,N,S,0) Analyses,

Selected Trace Element Scans using Quantitative Spectro­graphs Analysis with Atomic Absorption Techniques for Mercury,

Computer Assisted Electric Log Analysis using Guard, Resistivity, Gamma-Ray, Density, Neutron, Spontaneous Potential, and Caliper Logs.

*

Analysis of the core was in one-foot increments followed by blending of the intervals for a composite analysis of each saturated zone. Outcrop sampling was done by chip samples and in bulk using a bulldozer. Fifteen chip samples were averaged. Bulk samples were segregated into approximate thirds of low, medium and high grade and one composite was taken. Coring resulted in a total of 239 one-foot samples and 29 composite samples.

Toluene extractions were performed on all samples with the other analyses performed on selected composites. These data are illustrated on the adjoining figure.

In the area of immediate interest, covering wells 1A - 3\ and 8A - 10A, toluene extractable material averages 7.43 weight percent while the log analysis indicates 8.04

A-l

weight percent. This variation of 8.2% is probably within the limits of the techniques employed. 1)

The results of the other organic analyses are listed on Table 1. A summary of the trace elements is listed in Table 2. Sieve analysis indicates the parameters listed in Table 3.

The following conclusions may be reached and are considered valid for the area of the proposed mine:

- the grade, expressed as weight percent bitumen, increases in the near downdip wells

- hydrocarbon content increases dramatically from outcrop to the downdip wells reflecting evaporation and bacterial degradation

- oxygen content increases dramatically from outcrop to the downdip wells reflecting oxidation

- sulfur and metals content remain uniformly low throughout the section

1) It is my opinion that the log analysis may give a more accurate representation of the total bitumen in situ due to unavoidable problems in handling, the fact that the cored wells were not those logged, and statistical error in the laboratory analysis techniques. Excluding 2 outcrop wells (No. 3 & 4) a comparison of the toluene extracts vs. log analysis shows a variation of less than 3%.

A-2

TABLE I

(Figures Expressed as Weight Percent)

SOXHLET EXTRACTIONS

Composite Outcrop c h i p

of Bulk Samples

Toluene extract 4.12

Hexane 2.67 extract

Residual Py­ridine ex­tract

Chloroform extract

5.65

1A

7.94/ 7.522

7.402

8.04

2A

5.85^

^0.10

3A

7.93/ - . 4 . 8 9 / 7 . 6 6 1 5 . 0 6 2

3 .23

~ 0 . 1 0

9A

8 . 5 9 2

8 . 4 3 / 8 . 2 2 2

rvO.10

8.73

10A

8 . 6 1 / 8 . 5 5 1 / 7.07/-, 7 .03"

6 .90

^ 0 . 1 0

Saturates

Aromatics

Resins

Asphaltenes

SARA ANALYSIS

11.82

10. 02

10.02

68.22

27.22

31.52

18. 72

22.62

ULTIMATE ANALYSIS

Carbon

Hydrogen

Nitrogen

Sulfur

Oxygen

Total N,S,0

H/C

O/C

N.S.O/C

4 Chip Samples 78.29

9.51

1.25

0.41

6.00

7.68

0.121

0.077

0.098

83.79

11.23

0.85

0.45

2.68

3.98

0.134

0.032

0.047

82.92

11.23

0.64

0.43

3.24

4.31

0.135

0.039

0.052

84.53

11.29

1.00

0.48

1.16

2.64

0.134

0.014

0.031

85.33

11.28

0.93

0.47

1.56

2.96

0.132

0.018

0.035

1) Duplicate Analysis 2) Analyses performed by different lab

A-3

TABLE 2

TRACE ELEMENTS

(Expressed as parts per million)

Uranium

Thorium

Bismuth

Lead

Thallium

Mercury-

Tellurium

Antimony

Tin

Cadmium

Molybdenum

Selenium

Arsenic

Germanium

Gallium

Zinc

Copper

Nickel

Cobalt

Manganese

Chromium

Vanadium

3A

5A

9A

2A (Raw)

2

5

0.9

4

0.03

0.4

0.2

0.4

0.3

1

1

0.3

4

8

3

4

*• 0.1 >480

1

5

Mean Grain Size

0.20 mm

0.25 mm

0.17 mm

2A (Clean) 2

5

9

0.05

£0.4

0.9

3

12

1

0.2

6

15

12

2 ,

^0.3

110

11

8

TABLE 3

SIZE ANALYSIS

Median Grain Size

3.3tf

2.15<f>

2.35?$

9A (Raw) 2

5

9

0.5

0.02

0.2

0.9

2

0.9

2

4

0.5

7

8

2

5

^0.1

160

2

9

Sorting Coefficient

7.92

1.98

1.65

9A (Clean) 2

2

3

0.09

£,0.4

2

2

6

2

1

3

12

11

8

^0.3

640

22

14

Average Log Porosity

26.4%

25.7%

24.2%

A-4

STRUCTURE FENCE DIAGRAM - RAVEN RIDGE DEPOSIT, UTAH

T. 75, R. 25 E, SECTION 16

" ?\ ?\

D.H.I APPROXIMATE LOCATION

BULK SAMPLE

,D.H. 2

MVJ

N

D.H.8

D.H.3

to

D.H.4

iWv

D.H. 9^

^

D.H.IO\ i\W

•&/ <&» D.H.II

y / fc • ^ ̂

\r 10

N

4 400 800

DATUM : +5900' MSL

1400 3 I " : 400'

;50

D.H. 5

W

/

\ M

\\

I

m €d JD.H.6/

Wo D.H.7

i / • ? \o.H.ir . /

/ •? \>

16

21

LEGEND:

ND « NO DATA

TRC - TRACE SATURATION

. 4 WT % SCr 8 WT % TOLUENE

I I I ! I H

-

EXTRACT

D.H.I4