The process of taking out stones from natural rock beds is known as the quarrying. The term quarry is used to indicate the exposed surface of natural rocks. the stones, thus obtained are used for various engineering purposes. The difference between a mine and quarry should be noted. In case of mine, the operations are carried out under the ground at greater depth. In case of quarry, the operations are carried out at ground level in an exposed condition.

Site for quarry: The selection of site for a quarry of stones should be done after studying carefully the following aspects: i. Availability of tools, power, materials and labour for the easy and efficient working of quarry. ii. Availability of site for the dumping of refuse and avoiding health hazards, if any; iii. Distance of quarry from roads, railways, sea coast, etc. and proximity to the transportation facilities iv. Drainage of quarry pit v. Easy availability of clean water in sufficient quantity all the year round; vi. Economy in quarrying vii. Facility of carrying and conveying stones from quarry viii. For quarrying by blasting, absence of permanent structure in nearby area ix. Geological data regarding rock formations at the site x. Quality of stone available form quarry xi. Quantity of stones likely to be obtained from quarry xii. Results of trial pits etc.

Important Considerations for starting the quarry: Following are the important considerations which are to be carefully paid attention to before actually starting the quarry: a. Examination of rock surface b. Lay out c. Men and machines d. Removal of top surface e. Structural stability

Different methods of quarrying are as follows;

A. Quarrying with hand tools

Following are three different ways of doing quarrying by the use of hand tools: i. Digging: In this method, the stones are merely excavated with the help of suitable instruments such as pick axes, hammer, showels, chisel, etc. This method is useful when soft stones occur in the form of large or small blocks. ii. Heating: In this, method the top surface of rock is heated. This is usually done by placing pieces of wood or by piling a heat of fuel over the surface and setting a steady fire to them for some hours. Due to unequal expansion, the upper layer of rock separated out. It is indicated by dull bursting noise. The detached portion of rock is then removed by suitable instruments such as pick axes, crowbars, etc. iii. Wedging: In this method, if rock surface contains cracks or fissures, the steel wedges or points are driven through such cracks by means of hammers. The blocks of stones are then shifted and they are removed with the help of suitable instruments.

B. Quarrying with channeling machine

In this method, the channeling machines driven by steam, compressed air or electricity used to make vertical or oblique grooves or channels on the rock mass. These machines make rapidly the grooves having length of about 24m, width of about 50mm to 75mm and depth of about 2.40m to 3.70m.

C. Quarrying by blasting:

In this method, the explosives are used to convert rocks into small pieces of stones. The main purpose of quarrying stones by blasting is to loosen large masses of rocks and not to violently blow up the whole mass so as to convert it into very small pieces of practically no use. This method is used for quarrying hard stones, having no fissures or cracks.