hardrock

1. (mining) Rock containing ore from which minerals are extracted.Examples: "The federal system for "hardrocks," pursuant to the Mining Law of 1872, allows the discovery, location, and development of these minerals without payment to the federal government."; "Reflection coefficients calculated from impedance contrasts between felsic and mafic rocks and other common lithologies in hardrock terranes often exceed 6%, the estimated minimum value required to give strong reflections."; "In this context, you asked us to provide information on (1) which types of royalties the 12 western states assess on hardrock mining operations and (2) trends on imports and exports of hardrock minerals."countableuncountable

2. (geology) Solid, nonporous rock.Examples: "The Western U.S. sample was separated into the recording site categories of hardrock ( i.e., crystalline rock outcrop) , intermediate ( i.e., sedimentary rock or thin alluvium) and alluvium ( i.e., thick alluvium), and average residuals were computed for each of the three subsets."; "Its importance lies in the fact that hardrock areas cover the greater part of peninsular India. Moreover, many hardrock areas are drought-prone, making irrigation essential for reliable cropping."; "Being geologically characterised by shallow topsoil layers overlying the hardrocks of the Deccan, the groundwater resources in this ecozone are localised pockets of water percolating through fissures and cracks in the hardrocks."countableuncountable

3. (prison slang) An unregenerate criminal; a bully boy.Examples: "Rules and regulations and strict security measures used to hold hardrocks in line work against men trying to learn responsibility for themselves."; "As he looked around his eyes met those of two hardrocks, who sat on top of one of the speakers."; "Eight more stretch limos and 20 other cars followed behind the hearse, and through the windows people saw Ms. Wallace, Faith Evans, and the whole Bad Boy family and waved at them. Some waved their fists in a final triumphant gesture, saluting rather than celebrating. Tears flowed from the eyes of hardrocks and babymommas. No one could feel the cold anymore."countableslanguncountable