hardrock

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.

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.

The tension test specimens embedded to 45 mm (1 - 3/4 inch) in hardrock concrete generally failed when the tensile limit of the anchor itself was reached.

Rules and regulations and strict security measures used to hold hardrocks in line work against men trying to learn responsibility for themselves.