Claim: A quarry is where excavation of gravel occurs.

Open-pit , open-cast or open cut mining is a surface mining technique of extracting rock or minerals from the earth by their removal from an open pit or borrow .   This form of mining differs from extractive methods that require tunneling into the earth , such as long wall mining . Open-pit mines are used when deposits of commercially useful minerals or rocks are found near the surface ; that is , where the overburden -LRB- surface material covering the valuable deposit -RRB- is relatively thin or the material of interest is structurally unsuitable for tunnelling -LRB- as would be the case for sand , cinder , and gravel -RRB- . For minerals that occur deep below the surface -- where the overburden is thick or the mineral occurs as veins in hard rock -- underground mining methods are used to extract the valued material .   Open-pit mines that produce building materials and dimension stone are commonly referred to as `` quarries . ''   Open-pit mines are typically enlarged until either the mineral resource is exhausted , or an increasing ratio of overburden to ore makes further mining uneconomic . When this occurs , the exhausted mines are sometimes converted to landfills for disposal of solid wastes . However , some form of water control is usually required to keep the mine pit from becoming a lake , if the mine is situated in a climate of considerable precipitation or if any layers of the pit forming the mine border productive aquifers . Twin Creeks is most likely located in the northern part of Nevada .