Ore study of economic geology, or ore genesis. The classifications below are typical. The basic extraction of ore deposits follows these steps: Ores (metals) are traded internationally and comprise a sizeable portion of international trade in raw materials both in value and volume. This is because the worldwide distribution of ores is unequal and dislocated from locations of peak demand and from smelting infrastructure. Most base metals (copper, lead, zinc, nickel) are traded internationally on the London Metal Exchange, with smaller stockpiles and metals exchanges monitored by the COMEX and NYMEX exchanges in the United States and the Shanghai Futures Exchange
Broken Hill ore deposit mining is concentrated in the Blackwood Open Cut, which commenced in 1973, and the Kintore Open Cut. Stope fill, plus remnant supergene silver and sulphide ore characterize the ore reserve. Pasminco Limited took over the leases of The Zinc Corporation, Limited, and New Broken Hill Consolidated Limited. Their main shafts included ZC, NBHC and Southern Cross. These ZC Mines Leases lie south of the MMM Mining Leases along the Broken Hill "line of lode". By the early 1950s the Broken Hill area had suffered a major drought of over 8 years which was close to shutting down the mining operation.