DESIGN AND OPERATIONAL CONSIDERATIONS OF HARD ROCK AGGREGATE QUARRIES
DESIGN AND OPERATIONAL CONSIDERATIONS OF HARD ROCK AGGREGATE QUARRIES Author: Partha Das Sharma, B.Tech(Hons.) in Mining Engineering, E.mail: sharmapd1@gmail.com, Weblog: http://miningandblasting.wordpress.com/ 1. Introduction: Aggregates are the building blocks of our world. Often quarries are dismissed as ‘holes in the ground’ but, in reality, without quarries we could not build our homes, schools, offices, shops, hospitals, airports, roads and the infrastructure of our power and water systems. The dictionary definition of aggregate is ‘a rock, such as basalt, granite etc., consisting of a mixture of minerals’. There are three major sources of aggregates: ‘loose’ stones like sand and gravel; recycled materials; and solid rock like basalts, granite we quarry. Specifically, aggregates are defined as: “A granular material used in construction. Aggregate may be natural, manufactured or recycled.”
Natural aggregates account for a large proportion of minerals extracted domestically. There are two main types of natural aggregates: Crushed rock comprising: (a) Sedimentary rocks, created by the settlement of sediments (such as gritstones); (b) Igneous rocks which are solidified molten rocks (such as basalt or granite); and (c) Metamorphic rocks created by heat or pressure (such as quartzite). Sand and gravel. These are naturally occurring granular deposits that are found either on land or on the seabed. They are mostly loose, shallow deposits that have been spread over outcrops of solid rocks by the action of ice, water or wind. They are usually found in existing or historic river valleys, however, they may also occur in older, consolidated bedrock. Aggregates will continue to be an important resource as population growth and infrastructure demands increases.
1
PARTHA DAS SHARMA, B.TECH(HONS.) IN MINING ENGINEERING, E.mail: sharmapd1@gmail.com, Weblog: http://miningandblasting.wordpress.com/