Extraction Methods

This chapter reviews the main topics related to aggregate extraction from surface and underground methods. Although aggregate sources can be widely variable, the methods of extraction are very similar throughout the world, with crushed rocks mainly extracted from quarries (surface and underground mining) and sand and gravel from gravel pits. In the latter, the aggregate can be extracted above or below the waterline. These extraction methods are fairly well described together with loading and hauling equipment. Working hard rock quarries is a more complicated and intensive process than quarrying sand and gravel. Drilling and blasting in hard rock quarries are also briefly explained in this chapter because they are often necessary to extract the required rock. To illustrate the development of each mining method, several case studies are included in the text. The last heading of the chapter is devoted to marine aggregate extraction.