Advantages Of Surface Mining Method

Surface mining method are classified into the following two classes: [12]

• Mechanical

• Aqueous

As the deposit which is discussed in this thesis will be extracted by methods which exist in mechanical class, thus the aqueous class is discussed briefly and methods of the mechanical class are studied in detail. Aqueous class is dependent on water, in the manner that water is used for mining and processing of mineral through jetting, slurring, and dissolving. [13] Aqueous class is divided into two subclasses which are indicated in the following: [12]

• Placer

• Solution

The methods which are used in placer subclass is Hydraulicking and Dredging, and the methods which are related to solution subclass is Borehole mining and Leaching.

The aqueous

Open pit and open cast mining methods are the essential methods among four mechanical methods and also counted as most important methods between all eight surface mining methods. Open pit mining is done through one or numbers of horizontal benches. The removal ore and overburden is performed by the benches which vary in size starting from 9 meters up to 30 meters. A number of benches relate to the thickness of deposit, with increasing thickness of deposit the number of benches also increase and with decreasing of thickness it decreases. The shape of open pit may look like an inverted cone when the deposit is getting deep. If the deposit gets deep, also it can be extracted by adding benches. Some deposits can be extracted by single bench when the deposit thickness is between 15 to 45 meters.

This method is mostly used for the extraction of deposits which are nearly horizontal and mostly used in coal mining.

Quarrying is a mining method which is used mostly in extraction of dimension stones. According to Hartman L & John M (2002), quarrying is same as open pit methods but the benches (which is called faces in this method) are smaller and vertical. The dimension stone which is produced by quarrying method is generally used in monuments, decorations and etc. [15]

Auger or high wall mining is defined accordingly by Hartman L & John M (2002): [15]

“Auger mining is a mining method that recovers coal or other minerals from under the highwall when the ultimate stripping ratio has been achieved in open cast mining operations.”

The method can be described that, holes which is parallel to the coal seam is drilled into coal seam and brings out the coal from the holes. This method is also generally used for the extraction of coal from seams which are