Water Well Drilling Technique

Principles of Rock Drilling

Principles of Rock Drilling rock drilling used for the purpose of excavating rock by means of blasting. Other types of drilling, such as drilling for oil and water, mineral exploration, and grouting are excluded. The reader is given a brief explanation of the various prevailing drilling methods, as well as an introduction to blasting technique, and the interrelation of drilling and blasting. Also discussed are the main parameters involved when planning and executing blast hole drilling at quarries, open pit mines and various types of civil engineering projects. Drilling produces a circular hole in the rock, whose strength must be overcome by the drilling tool. Depending on rock properties, there are several ways to accomplish this. Rotary Drilling Rotary drilling can be subdivided into rotary cutting and rotary crushing. Rotary cutting creates the hole by shear forces, breaking the rock's tensile strength. The drill bit is furnished with cutter inserts of hard metal alloys, and the energy for breaking rock is provided by rotation torque in the drill rod. This technique is limited to rock with low tensile strength such as salt, silt and soft limestone not containing abrasive quartz minerals. Rotary crushing breaks the rock by high point load, accomplished by a toothed drill bit, which is pushed downwards with high force. The bit, being of tricone roller type fitted with tungsten carbide buttons, is simultaneously rotated, and drill cuttings are removed from the hole bottom by blowing compressed air through the bit. Drill rigs used for rotary drilling are large and heavy. The downwards thrust is achieved by utilising the weight of the drill rig itself, and the rotation, via a hydraulic or electric motor, applied at the end of the drill pipe. Common hole diameters range from 8 to 17½ in (200-440 mm) and, because adding the heavy drill pipes is cumbersome, most blasthole drillrigs use long masts and pipes to accommodate single-pass drilling of maximum 20 m (65 ft). Electric power is usually chosen for the large rigs, whereas smaller rigs are often powered by diesel engines. Rotation rates vary from 50 to 120 rpm, and the weight applied to the bit varies from 0.5 t/in of bit diameter in soft rock, to as much as 4 t/in of bit diameter in hard rock. Recent technical advances include: improved operator cab comfort; automatic control and adjustment of optimum feed force and rotation speed to prevailing geology and bit type and diameter; and incorporation of latest technology in electric and hydraulic drive systems. Rotary drilling, which is still the dominant method in large open pits, has limitations in that the rigs cannot drill holes off the vertical line. As blasting theories and practice have

proved, it is generally beneficial to design, drill and blast the bench slopes at an angle of approximately 18 degrees off vertical. Many rotary rig masts have pinning capabilities permitting drilling at angles as much as 30 degrees out of the vertical. However, the inclined hole drilling capabilities in rotary drilling are limited by the heavy feed force required, since part of this force is directed backwards. This causes rig stability problems, reduced penetration, and shorter life of drilling consumables. Consequently, most blast hole drilling using rotary drillrigs is in vertical holes. Percussive Drilling Percussive drilling breaks the rock by hammering impacts transferred from the rock drill to the drill bit at the hole bottom. The energy required to break the rock is generated by a pneumatic or hydraulic rock drill. A pressure is built

up, which, when released, drives the piston forwards. The piston strikes on the shank adapter, and the kinetic energy of the piston is converted into a stress wave travelling through the drill string to the hole bottom. In order to obtain the best drilling economy, the entire system, rock drill to drill steel to rock, must harmonise.

Water Well Drilling Techniques

James Rada, Jr. was a newspaper reporter for eight years and earned 23

awards from the Maryland Delaware D.C. Press Association, Associated Press, Society of Professional Journalists, Maryland State Teachers’ Association and CNHI. He also worked for 12 years as a marketing communications writer, earning a Print Copywriter of the Year Award from the Utah Ad Federation. He holds a Bachelor of Arts in communications. By James Rada, Jr.,

eHow Contributor

More than half the drinking water in the United States comes from wells. Sometimes the well is shallow because the water is close to the surface. Other times, the wells are hundreds of feet deep to get to aquifers deep beneath the ground. Different methods have been developed to get to the water depending on the depth it is below the ground and the type of ground that has to be penetrated to get to it.

1. Rotary Drillingo With rotary drilling, a bit is attached to the end of a length of drill pipe; additional pieces of

pipe can be attached as the hole deepens. A stabilizer is attached just above the bit to provide extra weight and help keep the drill hole straight. The drill pipe is hollow, and air or mud is circulated down the pipe out of holes in the bit. The air or mud then carries the cuttings up the side of the hole to the surface. The rotary drill bit is typically a tri-cone bit, which is actually three bits that work together to cut into the material.

Percussion Drillingo Percussion drilling is also known as cable tool drilling or spudding. The drill is raised using a

cable and dropped in the drill hole. The drill head rotates slightly with each drop to maintain a

circular hole. The impact breaks up clay and rock. The debris is mixed with water to create a slurry, which is then removed by a bailing device.

Jettingo In areas where the ground is sandier, jetting can be used. High-velocity water is shot into the

hole to break up the material. The water shoots through a chisel-shaped bit with holes in it. The water also keeps the drill bit clean as it breaks up the loosened earth. The water then washes the cuttings to the surface outside of the drill pipe.

Air Hammer Drillingo Air hammer drilling is a type of jetting that uses compressed air rather than water. The air is

shot into the drill hole against the earth to break up the rock. The air will also carry the cuttings up and out of the drill hole.

Hand Drivingo In areas where ground water is close to the surface, it is possible to hand drive the hole. This

begins by using a post hole digger to create a hole as deep as you can. A weighted driver is then used to drive casing into the ground using the percussion drilling method. Hand driving work best for wells that are less than 40 feet deep.

Auger Drillingo Auger drilling is similar to a hand driving. A spiral auger, in 5-foot lengths, is turned by a drive

head, allowing it to dig into the earth. The auger groove carries the cuttings to the surface.

Fractured bedrock can provide a significant source of groundwater for drinking or irrigation. If you are interested in installing a bedrock well, your state environmental department will be able to provide you with a list of competent drillers in your area. Mud rotary is a common drilling method for bedrock wells because it can drill through both the overlying soil and into the bedrock. Using proper installation techniques and materials, your drilling company will be able to install a high-yield, sediment-free water well.

How to Drill a Water Well in Rock

Instructions

1 Set the mud rotary drill rig at the chosen location for the water well. Attach the drill bit and drill rod

and set up the mud pan. Stack the remaining rods near the rig on the ground or on sawhorses to keep them clean.

2 Drill until you reach the top of the bedrock, attaching more drill rod as necessary. At this point, the

drillers either will prepare to case the borehole or will continue to drill into the top of the bedrock before installing the casing. The local water well construction requirements and/or the type of soil encountered above the well will dictate if the drillers will continue into the bedrock before installing the casing.

3 Install a solid casing into the borehole. The casing should be 1 to 2 inches in diameter smaller

than the borehole. Pump grout into the annular space between the casing and borehole walls. Some drillers may opt to install gravel in the annular space to within 20 feet or so of the land surface before injecting the grout. Your driller should follow all of your state's water well construction regulations. Allow the grout to cure.

4 Lower the drill bit through the casing and drill into the bedrock. Drill until you encounter fractures

with sufficient yield to support the water usage requirements for the property.

5 Install a well cap and a well cover to protect the casing from damage and contamination. Several

varieties of covers are available for different purposes, such as flush-mount, upright, vault and box covers. Ask the drilling company to recommend the most appropriate cover for the intended use of the well.

CONSTRUCATION DETAILS

Slot shape and sizeThe use of 'V' wire in fabrication of screen results in inwardly widening slots. The very shape of the slot in 'V' wire screen presents many advantages over the conventional slotted pipes or even round wire wound screens. In the slotted pipes the chances of blockage of the slots is highest during development process. The sand or gravel grains smaller or equal to size of the slot enter the slot and try to enter the inside of screen against very high friction

resistance. In most case they remain lodged in the slot and then still smaller particles tend to get lodged there till the entire slot gets blocked with silt and clay particles. Similar is the situation with round wire wound screens.

Shape of SlotsThe slot of the Star water well screens is unique in shape. The inwardly widening shape from the very edge of the slot allows only two point contact with any grain outside it. If the grain size is even marginally smaller, it slips in without facing any resistance and is then removed out of the well with the water. The larger grains remain outside. It is for this reason that Star Water Well Screens are known to be non clogging type. They allow the water to pass freely into the well with least friction.

Coupling with other Pipes Both ends of the screen are provided with threaded rings, welded to the vertical support rods for easy coupling with other pipes.

Hydraulic Efficiency of ScreensIt is an established fact that in most aquifers, the ground water flow is nearly horizontal. The orientation of the slots in the Star Water Well Screens are also horizontal. Thus flow of water from the aquifer into the screens present minimal resistance of the water flow, the flow remains non turbulent (laminar) and hence loss of head is minimal. In addition the continuous slot on star screens has clean the configuration of the slot is Designed to give high efficiency to the well. In other worlds the draw down due to well loss is minimized and the well yield high discharge at low draw down.

Open Area of the Star ScreensThe percent open area of the screen is ratio of the voids to solid part of the screen higher the percent open area means higher total open area per meter length of the screen. More the open area available for the water to flow into the well lower will be the entrance velocity and hence lower the head loss. The star water well screens have highest possible percent of open area as compared to there screens. Whereas the slotted pipes have the least open area (10-15 %) the 'V' wire wound screens have highest possible open area (14-50 %) without compromising on structural strength of the screen.

Collapse and Tensile Strengths of the Star ScreensThe constructional components of a continuous slot screen are selected to withstand the major stresses on the screens during construction and use of the well the column and the tensile strength required during well construction is provided by the longitudinal rods. The shape and massiveness of the wrapping wire provide the necessary collapse resistance needed during development and

long term use of the well.

Material of ConstructionThe Screen shall be made from wires of either of the following materials : (a) Low Carbon Galvanized (LCG) Steel (See IS 280)(b) Stainless Steel SS-304 (See IS 6528)The screens are classified as regular and heavy depending on well depth.

Pumps MotorsWith the necessary infrastructural requisites and the support of expert professionals, we

are capacitated to manufacture a wide variety of pumps. These pumps are fabricated as

per the set industrial recommendations and therefore we offer our range to the maximum

satisfaction of our clients. We are also able to offer tailor made solutions in accordance to

the industrial requirements. Following are some of the varieties in our diversified

assortment of pumps:

Bore Well Pump Motors

Our superior quality Submersible (Bore Well) Pump Motors - V 4 is fabricated with the usage of stainless steel and

other high grade engineering plastic components which makes them anti-corrosive and anti-abrasive. Thus, we avail

our range with greater operational efficiency and longer functional life. These are simple construction coupled with

precise parts ensures better and longer functionality.

Following are the special attributes of our Submersible (Bore Well) Pumps - V 4:

• Water lubricated wet type motor

• Water cooled

• Easily dismantled & repaired.

• Can handle up thrust loads

• Designed for withstanding wide voltage fluctuations.

The application areas of our Submersible (Bore Well) Pumps - V 4 includes:

• General purposes like domestic & community water supply, buildings, housing complexes and others

• Irrigation purposes like drip, sprinkler & open irrigation, gardening, seed farms, nurseries and others

• Industrial purposes where small water discharge is required at high pressure like dairy industries or low pressure

high discharge in industries, air conditioning installations, mining industries and many others.

Technical Specifications are as follows :

SPECIFICATIONS

Nominal Diameter 96 mm. (4")

Power Range

0.37 kw to 1.5 kw, Single phase

0.75 kw to 3.7 kw, Three phase

Speed 2800 RPM

Flow Rate (LPS) 0.25 - 4.5

Total Head Range 250 mtrs.

Nominal Outlet sizes 25 mm. (1"), 32 mm. (1.25"), 40 mm.(1.5"), and 50 mm. (2").

Version

50 Hz., 200 - 240 V A.C., Single phase

50 Hz., 380 - 415 V A.C., Three phase

Maximum Outer Diameter96 mm.

Type of Duty S1 (continuous)

Maximum Starts per Hour 6 times

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Centrifugal Pump Motors

We fabricate an extensive array of pump motors which also includes domestic centrifugal pumps. These are

manufactured with high grade materials and in accordance to the recommended industrial standards. These are

availed with superior mechanical shaft seal that ensures enhanced functionality and effective sealing against water

leakage. Moreover, the entire rotating components are dynamically balanced with its uni-casting volute chamber

designed to give higher hydraulic efficiency.

Following are some of the specifications of our centrifugal pumps:

• Resistant to wide voltage fluctuations & high temperature rise

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• Air locking is prevented by center delivery casing

• Good suction lift features &.greater water discharge rate & low power consumption

• Pumpset employs at 200 / 240 Volts, 50Hz. capacitor start & run, 2850 RPM & totally enclosed fan cooled motor

• Anti-friction ball bearings that are grease lubricated are fitted at both ends to withstand radial & axial loads

• Single phase motor without centrifugal switch facilitates easy maintenance.

Some of the application areas of our Centrifugal Pumps are:

• Irrigation

• Agriculture

• Farms

• Gardens Application areas include irrigation, agriculture, farms, gardens, industries & various other civil

applications.

Technical Specifications are as follows:

ECIFICATIONS

Power Range 0.37 kw to 1.5 kw , Single phase, 2pole

0.37 kw to 1.5 kw , Three phase, 2 pole

Speed 2850 / 2880 RPM

Version A.C.50 Hz., Single phase 200-240 V Permanent Split Capacitor (CSR)

A.C. 50 Hz., Three phase 380- 415 V Direct On Line (DOL)

Insulation ClassA / B


MATERIALS OF CONSTRUCTION

Pump Casing Closed Grain Graded Cast Iron

Motor Frame Closed Grain Graded Cast Iron / Aluminium

Impeller Closed Grain Graded Cast Iron

Send Enquiry

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Deep Well Pump Motors

Our specialized range of Deep Well Pump Motors- Model V 6 has widespread application in irrigation and other

purposes. These deep well pumps are precision engineered with the utilization of CNC machine which assures that

only flawless pumps are manufactured. Our pumps do not possess suction and priming problems and does not

require pump house.

Some of the salient features of our Deep Well Pumps- Model V 6:

• Noise-free operation

• High functional efficiency

• Highly durable water cooled rewindable motor

• Can be easily dismantled & repaired

• Specifically designed for wide voltage fluctuations.

Following are some of the application areas of our Deep Well Pumps- Model V 6:

• Rip & sprinkler irrigation

• Agriculture

• Public water supply

• Industrial and rural water supply

• Varied fields related to water supply.

ECIFICATIONS

Nominal Diameter 150 mm. (6")

Power Range 2.2 kw to 26 kw. Three phase

Speed 2850 RPM

Flow Rate 0.75 - 21 LPS

Total Head Range 9 - 250 mtrs.

Nominal Outlet sizes 50 mm. (2") and 65 mm. (2.5")

Operating Range 50 Hz., 380 - 415 V, A.C Three phase

Maximum Outer Diameter143 mm.


Maximum Starts per Hour 6 times

Method of Starting 2.2 kw to 5.5 kw Direct On line (DOL), 5.5 kw to 26 kw Star Delta (SD)

Jet Pump Motors

We fabricate and export an extensive range of Jet Pump Motors with the application of high end CNC machines

making them functional even during power fluctuations and low voltage. We have offered them with dynamically

balanced rotating parts, impellers and high quality single shaft for motor and pump. We can also customize them as

per the citations of our clients.

Cited below are some of the salient features of our jet pump set:

• Good suction lift

• Compact design

• Resistant to wide voltage fluctuations

• Servicing can be done with ease at minimal cost as the motor & pump are accessible at the surface.

Some of the application areas of our jet pumps are:

• Small farms

• Gardens

• Hotels

• Residents

• Small industries

• Various fields related to water supply.


PECIFICATIONS

Power Range 0.37 kw to 1.5 kw Single phase, 2 pole

0.37 kw to 1.5 kw Three phase , 2 pole

Speed 2850 / 2820 / 2800 RPM

Maximum Suction Lift 64 mtrs.

Discharge 400 LPH

Delivery Head Range 16 mtrs.

Version A.C. 50 Hz., Single phase 200 - 240 V,

Permanent Split Capacitor (CSR) and A.C., 50 Hz.,

Three phase 380 - 415 V, Direct On Line (DOL)

Class of Insulation A / B / E


Sealing Mechanical Seal (Carbon and Ceramic)

Nominal Pump sizes (Suction x Pressure x Delivery sizes in mm )40 x 32 x 25 and 32 x 25 x 25

Maximum Liquid Temperature 33 oC

Maximum Ambient Temperature 45 oC

Send Enquiry

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Monoblock Pump Motors

Send Enquiry

Openwell Submersible Pump Motors

We fabricate and export a wide assortment of quality based Open Well Submersible Pump Motors. We have

technocrats who design and fabricate our highly efficient and reliable Openwell Submersible Pumps. We have

developed our array in a manner which allows it to be easily dismantled and repaired.

Salient features of our Openwell Submersible Pumps are as follows:

• No suction & priming problems

• No requirement for pump house

• Noiseless operation

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• Highly durable water cooled rewindable motor

• Designed for wide voltage fluctuations.

Our open well submersible pumps are widely used for areas related to water supply such as:

• Irrigation

• Drip and sprinkler irrigation

• Agriculture

• Public water supply

• Industrial and rural water supply.


SPECIFICATIONS

Power Range

0.37 kw to 1.5 kw, Single phase

0.75 kw to 22 kw, Three phase

Speed 2880 / 2850 RPM

Flow Rate 0.2 to 65 LPS

Total Head Range 6 to 115 mtrs

Nominal Outlet sizes 50 mm. (2"), 65 mm. (2.5"), and 80 mm. (3")


Operating Range 50 Hz., 380 / 415 Volts A.C., Three phase

Maximum Starts per Hour6 times

Method of Starting

0.75 to 5.5 kw, Direct On Line (DOL), Three phase,

5.5. kw to 18.75 kw, Star Delta (SD) Three phase

Cable Connection Permanently connected and sealed PVC insulated 3 core flat cable.

Send Enquiry

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Self Priming Pump Motors

Leveraging on our infrastructural facilities, we are enabled to offer a superior array of Self Priming Pump Motors

which are reckoned for their hassle-free operations. The motor used in our self priming pumps is manufactured as per

IS: 996 which facilitate high starting torque. Our high end self priming pump does away with the use of foot valve and

have high and rapid suction properties. We avail our self priming pumps with C.I motor frame, gun metal and brass

impeller and stainless steel shaft that makes our range anti-corrosive.

Cited below are some of the salient features of our Self Priming Pumps:

Designed for wide voltage fluctuations

Vibration free smooth operation

Perfect head and discharge

Sturdy & compact design

Closed grain graded cast iron parts

Single & three phase options

High head due to regenerative action

Permanent split capacitor for single phase motor where centrifugal switch is not required

Superior water seal.

Following are some of the application areas of our Self Priming Pumps:

Pressure boosting and washing water circulation

Laundries

Hospitals and foundations

Offices

Dairies

Construction sites.


OPERATING LIMITS AND SPECIFICATIONS

Power 0.19 kw, 0.37 kw and 0.75kw (0.25 H.P and 1 H.P)

Frequency / Speed 50 Hz. / 2880 RPM


Flow Rate 0.93 LPS.

Total Head 50 mtrs.

Class of Insulation A / B



Maximum Ambient Temperature40 oC

OPERATING LIMITS AND SPECIFICATIONS

Power 0.19 kw, 0.37 kw and 0.75kw (0.25 H.P and 1 H.P)

Frequency / Speed 50 Hz. / 2880 RPM


Flow Rate 0.93 LPS.

Total Head 50 mtrs.

Class of Insulation A / B



Maximum Ambient Temperature40 oC

Documents

Water Well Drilling Technique