The project report includes Present Market Position and Expected Future Demand, Market Size, Statistics, Trends, SWOT Analysis and Forecasts. Report provides a comprehensive analysis from industry covering detailed reporting and evaluates the position of the industry by providing insights to the SWOT analysis of the industry.
Limestone is one of the most common minerals in the crust of the earth, and can be found all over the world as it covers about 10 % of the surface of the earth. It is a relatively young mineral and therefore it can be found near the surface. Limestone quarries are often open quarries, i.e. it is deposited from the surface and down. Limestone mines are not feasible from an economic point of view, as walls of limestone would have to be left behind.
The quarrying can be divided into five steps; overburden removal, drilling, blast- ing and transportation. First of all, the limestone has to be exposed. It can be found less than 1 m to tens of meters down in the ground. This is done by conventional excavators and is considered to be the most demanding part of the quarrying. When this is done, blasting holes are drilled. They are drilled with a twenty-degree angle, which has been shown to be most effective. Further on, the limestone is loaded onto lorries using excavators or rolling hoops. All steps in the quarrying have over the years been accurately developed to ensure as high profit as possible.
In Sweden, limestone is quarried at several places but the largest quarry is found near Slite, Gotland. The largest limestone quarry in the world is found near Roger’s city in USA, and is owned by Michigan Limestone and Chemical company.
Size reduction or comminution is the process; whereby particulate material is mechanically reduced in size, to increase their value and to bring them to a suitable size to use in important operations in various industries, eg. Cement, Stone, Coal, thermal power plants etc. Comminution processes are energy-intensive. In the mineral industries, coarse size reduction (from mined lump size to 1 cm.) is normally achieved by explosive shattering followed by crushing & grinding.
Where individual pieces are reduced in size by compression or impact. Fine size by compression or impact. Fine size reduction (from 1 cm. down to 10 micron) is typically achieved by grinding in tumbling mills, where particles break by probablistic impact in a loosely tumbling grinding media. Ultrafine size reduction (ie. smaller achieved by pulverizing where size reduction results by abrasion & attrition.
Solids may be homogeneous or heterogeneous, crystalline or amorphous hard or soft, brittle or ductile at large. However, most of the commercially important materials are heterogeneous & brittle, which fail catastrophically when stressed to a material can be measured by stressing a sample under closely controlled conditions of compression, tension or shear. Combination m/c works through compression or impact.
The devices used for combination, are required to provide a means for moving material into a stress-application zone for applying stresses to material for effecting combination and then, permitting the material to exit.
Thus, the line-up of m/c used must include provisions for machine dynamics based on breakage process. Generally, a combination device must perform (i) material breakage and (ii) material transport. While selecting a crushing, grinding & pulverizing mill the following factors should be carefully considered:–
(a) m/c should be capable of handling high tonnages
(b) m/c must operate efficiently to minimize operating costs.
The material transport mechanisms exist ranging from “simple gravity flow type” to complex combinations of gravity, mechanical and fluid flow. The relative energy consumption for material transport increases as the complexity of the transport mechanism increases.
