1 Terramin BIH Response Document Appendix C1

Updated Figures, Tables and Sections

The following sections of this document are to replace the item in the MLA or MPLA to which their number corresponds.

It should be noted that all tables and figures and text presented here superseded any tables, figures or text in the MLA and MPLA that may present

contradictory information.

2 Terramin BIH Response Document Appendix C1

Figure 3-88

3 Terramin BIH Response Document Appendix C1

Figure 3-89

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Table 3-51 | Proposed Outcomes and Closure Criteria Proposed Outcome Draft Measurement Criteria

Ensure the site is left in a stable, non-polluting state indefinitely

No adverse impact to the supply or quality of water by the mining operations to existing users and water dependant ecosystems

During rainfall events which generate runoff, three samples will be taken to measure turbidity at the car park, south-western drainage line, central drainage line (Goldwyn Creek) and at the overflow point of the surface water retention dam as per sampling method AS/NZS 5667.1:1998 standards.

A paired t-test will demonstrate that turbidity at the car park, south-western drainage line and at the overflow point of the surface water retention dam is not significantly greater (p-value ≤ t-test value) from the mean of the samples taken at Inverbrackie Creek upstream of the ML at that point in time over a consecutive period no less than 2 years.

Sampling will be undertaken once if possible within a 12 month period prior to Mineral Lease surrender document submission.

A report by an independent and suitably qualified expert (to DEM’s satisfaction) will verify once prior to application for surrender that all available information demonstrates that representative revegetation test sites have been rehabilitated to a safe, stable landform and have achieved, or by trends, may be confidently predicted to reach and pass sustainability thresholds as defined by Landscape Function Analysis (Sustainability thresholds for each parameter are interpreted as the points of maximum curvature on the sigmoidal curve shape as per Tongway and Hindley (2005).

Once prior to application for surrender, an audit/inspection of the final landforms conducted by a suitably qualified and experienced independent consultant, demonstrates that the final landforms are constructed to specifications and will be physically stable post mine completion.

No adverse impacts on soil quality within the mining lease that could compromise the post mining land use

Provision of a report once prior to entering the closure monitoring phase by a suitably qualified site contamination consultant verifies that a site contamination assessment and if required remediation in accordance with the NEPM and relevant EPA guidelines has occurred, ensuring there is no unacceptable risk to human health or the environment as a result of the contamination when compared with relevant baseline concentrations and relevant NEPM investigation levels.

Ensure all underground voids are filled to the extent that subsidence cannot occur at any time after mine closure.

An independent and suitably qualified expert (to DEM’s satisfaction) report will demonstrate that the risk of subsidence has been managed for the prevention of surface subsidence after cessation of underground mine operation.

Survey monitoring of mine void backfill to demonstrate mined production voids have been backfilled in accordance with PEPR methodology after cessation of underground mine operation.

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Proposed Outcome Draft Measurement Criteria

Ensure that no damage occurs to third party infrastructure and no injuries/ deaths result from collapse of the underground workings. Ensure that, in constructing and operating the lease, and post mine closure, that there are no public injuries/deaths resulting from unauthorized entry to the mine site. Ensure that upon mine closure, the site is left in a stable, non-polluting state indefinitely post closure Ensure that upon mine closure, the decline under Bird in Hand Road is to be backfilled in a manner to ensure the long term integrity of the public road structure

Surface survey monitoring will be undertaken every six months for the first year post underground mining cessation at 9 fixed geotechnical survey stations located along Bird in Hand Road.

Survey monitoring will demonstrate: - no differential settlement of more than 50mm or as compared to baseline subsidence monitors located on Pfeiffer Road, over a 1 year period immediately after the cessation of underground mining.

An independent and suitably qualified expert (to DEM’s satisfaction) conducts a construct to design audit of the vertical entrances into the mine (shafts) against the design and confirms that shafts have been backfilled and constructed to design specifications within three months of the completion of the shafts being backfilled.

An independent and suitably qualified expert (to DEM’s satisfaction) conducts a construct to design audit of the decline plug against the design and confirms decline has been backfilled and constructed to design specifications within three months of completion of decline being backfilled.

No adverse impact to the supply or quality of water by the mining operations to existing users and water dependent ecosystems.

An independent and suitably qualified expert (to DEM’s satisfaction) will review all groundwater data geochemical groundwater data and numerical groundwater modelling (groundwater levels and water quality) developed for mine void recharge scenario to verify no adverse impact to the supply or quality of water by mining operations to existing users and water dependent ecosystems by reviewing all data collected pre-mining, operations and closure, once prior to application for surrender.

No permanent loss of abundance, condition or diversity of native vegetation (as defined by Native Vegetation Act 1991) on or off the lease during construction, operation and post mine completion through;

• clearance,

• dust/contaminant deposition,

• fire,

• reduction in water supply, or

• other damage,

unless prior approval under Native Vegetation Act 1991 and Native Vegetation Regulations 2017 is obtained.

An independent and suitably qualified expert (to DEM’s satisfaction) verifies once within 24 months before submission of surrender application through a report that representative revegetated areas have achieved or by trends may be confidently predicted to reach and pass sustainability thresholds as defined by Landscape Function Analysis (Sustainability thresholds for each parameter are interpreted as the points of maximum curvature on the sigmoidal curve shape as per Tongway and Hindley (2005).

Survey of heritage trees by an independent and suitably qualified expert (to DEM’s satisfaction) demonstrates that heritage trees (MCP Appendix AD) have not been impacted by mining activities through rehabilitation and closure phase

The form, contrasting aspects and reflective aspects of mining structures are visually softened to blend in with the surrounding landscape.

Upon completion of rehabilitation activities independent verification and a photo point assessment will demonstrate that the Strategic Visual Amenity Plan (G1) and Concept Closure Plan (X1) has been fully implemented.

The Lessee must ensure that upon mine closure, all plant and equipment (unless otherwise agreed with the Chief Inspector or Mines or authorised representative) is removed from the site.

Upon completion of rehabilitation activities, a visual assessment of the proposed ML will demonstrate all metalliferous mining plant, equipment, infrastructure and rubbish has been removed from site (unless otherwise agreed with the Chief Inspector of Mines).

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List at Section 3.4.6.7 • Pre-excavation grouting, inflow to be pumped to surface and managed aquifer recharge (MAR);

• Post-excavation grouting;

• Emergency de-watering pump(s);

• Design of a scalable underground pumping systems;

• Capacity and scalability of water treatment infrastructure to manage unexpected high inflows;

• Regular monitoring and testing processes (i.e. probing, flow meters, level indicators and alarms in sumps and tanks etc.) and continuous improvement

system for risk management.

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Section 3.4.2.7.5 The following case studies are to be included in the list at section 3.4.2.7.5

3.4.2.7.5.6 Boliden Tara Mine (Excerpt Tara Groundwater Management Plan)

Main Product: c200ktpa zinc/lead concentrate: Mining Method: Underground, open stoping and some room and pillar.

The Excerpts from the Tara Groundwater Management Plan demonstrates the approach to grouting in a similar mine to BIHGP. It outline several control

measures which are in place to monitor the effect of ongoing mining.

“Important outputs are:

• Verification of the position of the cone of depression (groundwater) around the perimeter of the active mine i.e. does observations confirm the

model; and

• Verification that the grouting from the hanging wall drifts are effective.”

Groundwater monitoring

Two control measures are in place to monitor the groundwater table:

1. Groundwater level “is monitored through piezometers and/or manual dipping of surface drill holes”; and

2. “Groundwater quality (hydrochemistry and temperature) is monitored.”

“Monitoring the groundwater table provides information of the water compression zone around the mine and what water head that can be expected

underground.”

Probe drilling

Probe drilling occurs in two stages:

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1. Probe drilling from hanging wall drifts: this occurs “[a]s the mine expands into new areas … Upon completion of the probe drilling program, the holes

are high pressure grouted to create a curtain above the future mining blocks below.”

2. Probe drilling from the mining horizon: this “comes after the hanging wall probing … [and] has a dual purpose [to] assess the effect of the hanging wall

probing [and to] drain the water that remains in the rock mass below the grout curtain.”

Other controls

“[I]t is part of the mine’s procedure to [also] do a set of shorter (3x10m long) probe holes to for each development round. If water is intersected this will be

recorded on the shift log under matters relating safety. Where the development is advancing towards know water bearing structures, full profile grout curtains

are installed that creates a seal around the full profile of the drift.”

3.4.2.7.5.7 Northern Star Pogo Mine (Sumimoto Metal Mining Pogo LLC, 2011)

Mining Method

“Cut-and-fill mining is the primary mining method used at Pogo. This method is selective and yields a high overall ore recovery at a low dilution factor, as

mining conforms to the shape of the deposit. All production drilling is conducted by rubber tired drill jumbos. After the stopes are mined, paste backfill is

used to fill all mining voids.”

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Mine Water

“Pogo began grouting in 2009, and it significantly contributes to controlling the underground seepage. Curtain grouting is applied to grout the water bearing

faults such as Liese Creek ahead of advancing drifts. When water inflow is found in the drift, 60 feet long grout holes are drilled using a jumbo at the perimeter

of drift, and then fine ground cement mixed with water is pumped into the holes at high pressure using a grout pump through mechanical packers set at the

collar of grout holes. A couple of check holes are drilled after 24-hr curing time. Secondary grouting may be conducted if water inflow still exists. After

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completing the grouting procedure, the drift is advanced by 40 feet and is grouted again. If the water inflow can’t be controlled by grouting, this stope may

be paste backfilled.”

Northern Star Pogo Mine (Sumimoto Metal Mining Pogo LLC, 2014)

Conclusions

“The grouting program that is currently in place serves to seal some or most groundwater from the working areas. Not allowing the mine to drain means that

groundwater is not depleting and, unlike in some other mines that freely drain, a diminishment of inflow as a result of groundwater depletion over time

from drainage is not likely. Grout sealing can leave the water behind the grout in place, available for inflow when or if other transmissive features are

intercepted by mining. What this means is that unless discharge limits are substantially increased, and the capacity of pumping and piping increased, Pogo

will have to continue grouting throughout the life of the mine. Probe holes into areas planned for mining can help in anticipating short term inflow controls

and long term grouting requirements.”

3.4.2.7.5.8 Zhuxianzhuang Coal Mine (Gao, Xicai, et al, 2018)

“the polymer two-component chemical grouting materials and pregrouting construction technology, which have the functions of both water plugging and consolidation were put forward. Thus, the water burst passing over the drift-sand layer under complicated conditions was effectively controlled, and the shaft construction progress and safety were ensured.”

Engineering Application of Chemical Pregrouting

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Multistep Grouting Construction Technology

“Considering the specific engineering geological conditions, the multistep pregrouting and rapid construction technology is used for construction of the shaft according to the experience of water prevention and control in nearby mines.

“The shaft construction reveals that the seepage channels of surrounding rocks are mainly holes with weak permeability. The alkaline water has a negative influence on the reaction of the grout and the durability of curing materials.

“The compound chemical grouting materials (i.e., sand curing material MGS and water plugging material Midwest213) with lower viscosity and controllable curing time are selected. The sand curing material MGS also has other advantages such as higher safety without aldehyde, acid and alkali resistance, and fire resistance; thus, MGS is applicable in an aquifer of sandstone, which is rich in soluble salts, drift-sand layer curing, and water inflow plugging.”

Multistep Pregrouting Design Scheme

“A concrete wall was first constructed at the driving face in the shaft passing over the drift-sand layer with a thickness of 600 mm. A relief hole was set in the middle bottom of the wall with a hole diameter of 80~100 mm.

“In order to leave the grout enough time for reaction and curing before flowing to the relief hole, the grouting holes were drilled using the common electric coal drill from the bottom to the top. A specific method was used for water plugging and drilling at the location where the sealing wall was far away from the water exit along the roadway border, and the chemical grouting material Midwest213 was used for water plugging. And then, the water flow in the drift-sand layer inside the sealing wall was relatively stable.”

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Rapid Curing of Rock Mass Grouting at the Drift-Sand Layer

“The sealing wall was used as a grouting pad at the jointing part between the vertical wall and the concrete shaft at the middle lower part of the sealing wall. … Grouting can be started after confirming that preparation has been made.”

Results Evaluation and Discussion

“The comprehensive construction method of self-closing, highest priority water plugging, and secondary sand curing at the drift-sand layer is confirmed. Two liquid compound chemical grouting materials with lower viscosity and controllable curing time are applied on the sand curing, water plugging, and grouting for shaft passing through the drift-sand layer.”

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“Twelve water plugging and grouting drill holes were set on the sealing wall. … Water flow at the drift-sand layer inside the sealing wall of the shaft was relatively stable. The sealing wall was used as a grouting pad. About 28 holes with a depth of 350mm were drilled for sand curing construction. ... A rock sample was drilled after grouting construction was finished to evaluate the grouting effect. No water burst and sand drifting phenomenon and the solidified bodied strength were stronger after the sealing wall was broken. Sand curing and water plugging effects are prominent. Thus, the water burst passing over the drift-sand layer under complicated conditions is effectively controlled, and the normal excavation speed of the shaft is guaranteed.”

3.4.2.7.5.9 Black Butte Gold Mine (Geomin Resources)

Pressure Grouting and Groundwater Inflow Control Plan

“Pressure grouting will be the primary means of minimizing and controlling the amount of water flowing from water-bearing faults and fractures, into the

mine workings. … Grouting both strengthens the rock and reduces water flowthrough fractures, and is a widely accepted standard practice in the mining

industry for controlling mine inflow.”

“Pilot holes are typically drilled into the projected mine workings ahead of the advancing / active mining face and are used to test for larger water inflow

rates in the vicinity of anticipated waterbearing geologic structures. Large amounts of water encountered in a pilot hole require installation of a packer to

seal-off the flow of water from the hole followed by directional drilling and grouting of fractured wall rock adjacent to the projected workings prior to

advancing the drift/tunnel through the zone.”

“In fracture flow controlled systems, mining into a water-filled fracture will typically see a significant decrease in hydrostatic head (and therefore flow rate)

over periods of one to several days or less. Therefore, only sustained water flows of generally 10 to 20 gallons (38 to 76 L) per minute or larger are typically

grouted off when detected in pilot holes. … Most production mining stopes are generally not grouted (because of the cut and fill mining method). Sustained

inflows into ventilation raises from distinct fractures are almost always grouted regardless of the inflow rate in order to minimize inflow into the raises.”

“When all the fractures intersected by all of the drill holes in the drilled pattern around the workings are grouted, a grout curtain is built around the drift/tunnel

that forces water to flow around the workings and eliminates/minimizes water from entering the drift/tunnel.”

3.4.2.7.5.10 Shenhua Coal Mine (Sui, 2014)

Introduction

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“Generally, drainage and grouting are two main methods to ensure mining safety above limestone aquifers. Drainage will decrease the water table by

powerful pumping. …Therefore, it is necessary to employ grouting project to ensure the coal mining safety. Grouting will enforce the strength of bed rock

that underlie the coal seam and seal the inherent geological structures such as faults and fractures. Moreover, grouting project is more economical and

environmental friendly than drainage.”

Coal mine grouting principles

“The objectives of coal mine grouting project are reducing the permeability and deformability of rocks between water-conducting failure zones and aquifer.

It is also used for increasing rock strength against shearing forces.”

“Grouting projects have three important components including the design, implementation and quality testing of the placed grout. Grouting design requires

a good knowledge of geological conditions and grout flow theory. Therefore, the investigation should be carried out to gain a good understanding of geology.

In addition, choosing one appropriate grout material and applying relative grout flow theory are necessary.”

“The feasibility, durability, costs and time consumption are most important aspects in grouting design (Giovanni 2004). Moreover, drilling and grouting

equipment is needed to implement grouting design. At the final stage, grouting quality should be tested to verify the effect.”

Case study: Xinyi coal mine

Two important points are:

• “a detailed geological investigation should be carried out in this panel to make the grouting design more effective”.

• “a geophysical transient electromagnetic technique … is suitable to detect water because of its low resistivity”.

Grouting project

Design

“The grouting target is to prevent water inrush from two abnormal water areas, as well as reduce costs. Therefore, the grouting boreholes should be arranged

at abnormal water areas with different depth so that the grouting slurry can form a thick barrier.”

“Considering the effect of group boreholes grouting, three neighbouring boreholes should be arranged at corner of triangle with distance no more than 35

m.”

Implementation

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“Drilling fields with the dimension of 4.5 × 3.5 ×3.5 m (length × width × height) were constructed to implement drilling. The borehole was drilled in three

stages because the high confined water pressure. … The grouting was implemented at the pressure of 12 MPa with the volume ranges from 1 to 2 t.”

Quality control

“Quality control in this project includes grout material test and permeability test. Tests on grout material were conducted on water and suspension.”

“Transient electromagnetic technique was employed to test permeability and verify the quality of this grouting project.”

Results

“The water inflow rate was less than 5 m³/h during mining of this panel from December 2011 to June 2012 and around 800 kt of coals were safely excavated.

This grouting project was considered as a successful case.”

Conclusions

“Grouting can be considered as a feasible method to ensure the coal mining safety under high confined water pressure.”

3.4.2.7.5.11 Lisheen Mine (Talbot and Burke, 2013)

At Lisheen, there were a number of backfilled stopes where they had to prepare for and manage ongoing water into the backfill. They implemented drainage

pipes underneath the backfill (pre-backfill).

“The introduction of paste backfill allowed for long hole open stopes and more aggressive pillar mining. The introduction of cable bolting facilitated the design

of larger spans and shotcreting provided stability to slender pillars and surface support to fractured and weathered ground.”

“The predrilling and high pressure grouting of a grout curtain ahead of the face showed promise but was time consuming and unpredictable.

“The introduction of drill-and-forget spiling bars followed by pressure grouting has allowed both the consolidation (comment as before) and reinforcement

of ground ahead of the face. This has proved to be quicker and easier to implement and gives more control over the pressure grouting. This support technique

combined with good blasting design has allowed the mine to access areas that previously were considered unmineable.

“The use of long bulbed cables, fibre-reinforced shotcrete and high pressure grouting with drill and forget spiles have now become a ground control

management tool at Lisheen allowing the safe and economic extraction of high grade ore stopes in extremely poor ground conditions.”

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“Mining methods used are a combination of room and pillar, drift and fill and increasingly long hole open stoping (LHOS) at depths of between 70 and 230

m below surface.”

Mining methods

“Long hole open stoping is commenced by driving a primary drive along the footwall, supporting as required with rebar, shotcrete and cables. Once the

development is complete in areas where poor ground has been identified, pre-support in the form of long bulbed cables are drilled through the orebody and

at least 5 m into the hangingwall or solid ground. The entire cable length is encapsulated in grout.

“Once completed the production drilling starts and the stope is retreated on a ring by ring basis utilising remote mucking. Some of the stopes at Lisheen can

be up to 30 m high, 25 m wide and 100 m long with individual blasts of between 2,000 and 10,000 tons. Without pre-support weathered zones above the

hangingwall would cause significant overbreak, dilution, air blast and possibly caving.”

Drift and Fill

“Drift and fill mining is utilised in areas where the ore is not thick enough to justify stoping and not thin enough to room and pillar. Lisheen uses a modified

method slashing the 6 m wide primary development drive out to 10 m on retreat. The drift is then paste filling while developing the parallel drift leaving a 10

m pillar in between. The use of long holes and remote mucking to retreat the sidewall slash ensures a quicker and safer turnaround of the stope. Careful

sequencing of the extraction ensures that the secondary drifts are removed from the centre to the abutment of the panels. This has successfully allowed the

total extraction of panels of greater than 150 m in extent.”

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Room and pillar

“Primary development is carried out using a conservative pillar strength design with a factor of safety of two. This produces a squat pillar usually 8 × 10 m

and is verified by numerical modelling and close observation of the development. Panels are designed around the orientations of major structures and ground

conditions. A suitable hydraulic radius would be designed for the panel that could vary from three in very poor ground to a maximum of 25 in very good

ground. A strict protocol to ensure the maximum safe extraction of the panel is used that includes pre-drilling pillars, remote mucking, monitoring of both

the roof beam and pillar behaviour and strict adherence to the individual pillar removal sequence.”

Ground consolidation (strengthening and reinforcement)

“Primary grouting is conducted using a low pressure pump in order to fill the annulus of the hole with grout. A plug and breather tube is installed at the collar

in order to ensure that the area around the collar is fully grouted. When the primary grouting is complete the bore of the drill string is washed out and the

grout allowed to set for 8–24 hours.

“The drilling of the spiles and acceptance of the primary grouting will decide if pressure grouting is necessary to further consolidate the ground. Based on this

information a mix design is made specifying the grout and pressures for each hole. This can vary from high Blaine micro cement with plasticiser to Ordinary

Portland Cement depending on the void ratio and porosity of the ground.

“A high pressure colloidal mixing pump is attached to the collar of the threaded bar which is now fully grouted in place and unable to move. The high pressure

delivered by the pump breaks open the ‘valves’ and the thin recently set grout around the valves and allows grout to be placed at high pressure at various

points down along the drill string all the way to the bit at the head of the string. This technique allows control of the placement of grout ahead of development

ends as well as re-enforcing the roof with grouted spiles.”

Conclusions

“A combination of advanced support techniques and accurate and holistic geotechnical data analysis at the Lisheen Mine has significantly assisted in the

management of the safe extraction of mining areas in extremely poor ground conditions and in some circumstances has extended the mineable reserve.

“Although many of the techniques used in managing the poor ground are site specific, they are applicable to many different ground conditions and have the

potential for realising benefit for any mining operation. The technique applied at Lisheen is about getting the best out of the support resources available while

exploring new inexpensive means of broadening the support tools available. At the same time geotechnical engineers are using all the information available

to accurately predict variations in ground conditions in an individual panel and the likely geotechnical risks that are going to be encountered.

“The technique applied is a fresh approach contrary to the usual mining response of throwing more and more resources at the problem. The changes made

to the support processes at Lisheen will allow the operation to achieve maximum extraction safely, as the mine comes into its final stages.”

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3.4.2.7.5.12 Diavik Mine (Rio Tinto, 2017)

Diavik had to manage water through their backfill in their A154N pipe. One of the measures they implemented to mitigate the environmental impact to the

surface and ground water is the design and construction of bulkheads “to prevent the flow of PK material or decant water into the A154 mine”.

Bulkhead Construction

“Contact grouting will be done around the bulkheads in an effort to prevent seepage”

“Should these inflows within the rock mass be higher than 5 gpm, DDMI may conduct additional grouting to control the seepage”

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Section 14.7.1 of Miscellaneous Purposes Licence Application 14.7.1 BIH Ore The results of the geochemical analysis of the BIH ore zone (Table 14-7), Indicate that all metals measured are below the levels observed in AZM Ore. No

elevated uranium or thorium assays have been recorded at Bird-in-Hand and petrological studies indicate that there are no asbestiform minerals or minerals

that have the potential to produce respirable silica.

TABLE 14-7 | BIH MINERALISATION COMPARED TO AZM MINERALISATION

Bird-in-Hand Angas Zinc Mine

Metal Peak individual

grade peak (mg/kg)

Average block model (mg/kg)

Peak individual grade peak (mg/kg)

Average block model (mg/kg)

Arsenic 869 27 89,600 216

Beryllium 9 7.83 0.67

Boron Below detection 40 20

Cadmium 228 1,047 283

Chromium 348 53

Cobalt 398 104 47

Copper 15,900 390 10,835 1,900

Lead 478,000 2,700 363,000 33,700

Manganese 10,968 13,700 1,973

Mercury 13 16.6 0.19

Nickel 1,033 117

Selenium 43 2.6

Zinc 136,000 3,100 484,000 76,800

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Response to question 100 - Location of Ventilation Shaft