Like what you see? Ask us for a full-length preview and pricing options for our entire course catalog
Request full preview
The terms open-pit and opencast refer to the type of surface mining which results in a depression or deep funnel-shaped pit surrounded by sloped or stepped walls. At these types of surface mines, a material's hardness ultimately determines how it will be extracted. Softer, unconsolidated material, such as sand and gravel, clay, and some minerals, can be mined by heavy digging equipment. If the material is under water, dredging equipment is used to bring deposits to the surface for processing. Harder, consolidated materials such as granite, marble, and limestone may require drilling and blasting for efficient removal. An open-pit mining operation which regularly uses explosives is referred to as a quarry.