Boart Longyear samples for the proposed Golden Gate Bridge in San Francisco. In spite of the financial crisis, the 1930s saw improvements in diamond drilling technology, including the use of industrial-quality diamonds mined in Africa that were called “boarts.” In 1936, South Africa’s Anglo American Corporation formed Boart Products South Africa (Pty) Limited, which was later named Boart International. The new company developed the first mechanically-set diamond core bits, which were less expensive than the hand-set core bits that used more expensive Brazilian diamonds (carbonados). Longyear’s business gradually improved in the 1940s in response to expanding worldwide mineral exploration. In 1949, the
Radioactive waste or at least closure, of several sites. Radioactive medical waste tends to contain beta particle and gamma ray emitters. It can be divided into two main classes. In diagnostic nuclear medicine a number of short-lived gamma emitters such as technetium-99m are used. Many of these can be disposed of by leaving it to decay for a short time before disposal as normal waste. Other isotopes used in medicine, with half-lives in parentheses, include: Industrial source waste can contain alpha, beta, neutron or gamma emitters. Gamma emitters are used in radiography while neutron emitting sources are used in a range of