শব্দের চেয়ে ছবি দিয়ে বোঝাতে ভালবাসি

The equipment used includes: draglines, which remove the overburden (the term given to the strata between the coal seams and the surface); power shovels; large trucks, which transport overburden and coal; bucket wheel excavators; and high capacity conveyors. Surface mining equipment has increased dramatically in size over recent years. However, in some countries, the high capital cost of importing this equipment can favour the selection of underground mining. http://www.australiancoal.com.au/methods.htm