Mohammad Esa Rasuly Esarasuly4@gmail.com III-B.Tech Mining

GIET (A) Rajahmundry

Underground Mining An Overview

Underground mining is a technique used to access ores and valuable minerals in the ground by digging into the ground to extract them in an economical way. Underground mining is carried out when the rocks, minerals, or precious stones are located at a distance far beneath the ground and it is not economical to be extracted with surface mining.

Introduction

› The ore deposit is deep.

› Grade is high enough to mine profitably.

› Where surface mining is not economical.

› Certain conditions which surface mining is not permissible such as:

If there is reserve forest.

If there is river flowing beside or one the ore deposit.

If there is habitation area.

When we go for Underground Mining

Depending upon the type of rock the method of working will be chosen. Underground Mining Methods are usually classified into two categories which are as follows:

I. Underground Mining (Hard Rock). II. Underground Mining (Soft Rock).

Methods of Working

Underground hard rock mining refers to various underground mining techniques used to excavate hard minerals such as those containing metals like gold, copper, zinc, nickel and lead or gems such as diamonds.

Underground Gold Mine (Hard Rock) Photo from: www.google.com/images

Underground Mining (Hard Rock)

Underground mining (soft rock) refer to a group of underground mining techniques used to extract minerals such as: coal, oil shale, Salt, Uranium, Phosphate and other minerals or geological materials from sedimentary ("soft rocks"). Because deposits in sedimentary rocks are commonly layered and relatively less hard.

Underground Coal Mine (Soft Rock)

Underground Mining (Soft rock)

Underground coal mine (soft rock) photo from: www.google.com/images

Based on Hard Rocks Underground Mining methods can be classified as follows:

• Short-hole and Long-hole Underground Mining Methods.

• Selective and Unselective Underground Mining Methods.

• Supported and Unsupported Underground Mining Methods.

Methods Applicable For Hard Rock Mining

Based on the Soft Rocks Underground Mining methods can be classified as follows:

• Longwall Mining Method.

• Shortwall Mining Method.

• Room and Pillar Mining Method.

• Blasting Gallery Mining Method.

• Coal skimming Mining Method .

Methods Applicable For Soft Rock Mining

In order to access underground ore minerals removal of overburden is required which can be done in any of these three ways :

1. Vertical Shaft

2. Decline (or) Ramp

3. Adit

Underground Access

Levels are excavated horizontally from decline or shaft to access the ore body. Stopes are then excavated perpendicular (or near perpendicular) to the level into the ore.

Ore Access

› Continues Miner.

› UDM(Universal Drill Machine).

› LHD(Load Haul Dumper).

› Shuttle Cars.

› Belt conveyors .

› Chain conveyors.

› Rope haulages.

› Locomotives.

Different Types Of Machinery and Transport System Used In

Underground Mines

Manual Drilling Drilling with UDM

Photos from: www.google.com/Images

LHD(Load Haul Dumper)

Conveyors

Photos from: www.google.com/images

Support System In Underground Mines

• Chocks • Props • Hydraulic supports • Roof bolting• Roof stitching • Steel arch

Based on the characteristic of rock, systems of supports maybe chosen, some types of supports are as follows:

Ventilation  Underground mine ventilation provides a flow of air to the underground workings of a mine of sufficient volume to dilute and remove dust and noxious gases typically (NOx, SO2, methane, CO2 and CO) and to regulate temperature. The source of these gases are equipment that runs on diesel engines, blasting with explosives, and the orebody itself. The largest component of the operating cost for mine ventilation is electricity to power the ventilation fans, which may account for one third of a typical underground mine's entire electrical power cost

› Drinking Water:

› Mine water:

Handling of Water

› Underground mining is more ecofriendly than surface mining and it could be carried out when the ore deposits are at a higher depth and the various methods are applicable for extraction of different minerals such as coal, gold, copper, iron, salt, diamond, etc. in an economical way.

› We should keep in mind that Underground mining is more Hazardous than surface mining. Noxious gases are present hence we need to take precautions. In underground mining arrangement should be taken for lighting, ventilation, support systems, dewatering, etc.

› In Underground mines we can use low and permitted explosives only.

Conclusion

› The presenter wish to acknowledge the Management and faculty members of GIET college specially Mining and Petroleum branches for providing an opportunity to do this task.

› And also the presenter acknowledge the parents, friends for their continuous encouragement in doing this work.

Acknowledgment

› http://www.howstuffworks.com › http://www.google.com › http://www.google.com/images › http://www.Wikipedia.org

References

Thank you!