Copper world reserves

Copper. World copper reserves are estimated at 408.167 > t copper one-fifth being in the United States. Requirements for fertilizer are very... 

Deposits. Selenium forms natural compounds with 16 other elements. It is a main constituent of 39 mineral species and a minor component of 37 others, chiefly sulfides. The minerals are finely disseminated and do not form a selenium ore. Because there are no deposits that can be worked for selenium recovery alone, there are no mine reserves. Nevertheless, the 1995 world reserves, chiefly in nonferrous metals sulfide deposits, are ca 70,000 metric tons and total resources are ca 130,000 t (24). The principal resources of the world are in the base metal sulfide deposits that are mined primarily for copper, zinc, nickel, and silver, and to a lesser extent, lead and mercury, where selenium recovery is secondary. 

As indicated in the Product Assessment Matrix (Table 5), an environmental assessment of mining metal must consider the energy consumption and the solid, liquid and gaseous residues that result from the various mining processes. Availability of the metals is an additional consideration. Table 6 lists the world reserves of the major metals typically utilized in electronic assemblies. Sn-Ag-Cu alloy is one of the major compositions proposed as a replacement for Sn-Pb solder. Silver is 300 times less available than lead. Half of the silver available comes as a by-product from mining lead, copper and zinc. Antimony and bismuth are also obtained as by-products of lead, copper and silver mining. 

Resources. World resources of silver are estimated to be about half a million tons. However, only about 250,000 metric tons are considered economically recoverable reserves. These are associated with ores of copper, gold, lead, and 2inc, and extraction depends on the economic recovery of those metals. Canada and the CIS vie for the greatest reserves of silver in the ground. 

More than 200 ores are known to contain cobalt but only a few are of commercial value. The more important are arsenides and sulfides such as smaltite, C0AS2, cobaltite (or cobalt glance), CoAsS, and linnaeite, C03S4. These are invariably associated with nickel, and often also with copper and lead, and it is usually obtained as a byproduct or coproduct in the recovery of these metals. The world s major sources of cobalt are the African continent and Canada with smaller reserves in Australia and the former USSR. All the platinum metals are generally associated with each other and rhodium and iridium therefore occur wherever the other platinum metals are found. However, the relative proportions of the individual metals are by no means constant and the more important sources of rhodium are the nickel-copper-sulfide ores found in South Africa and in Sudbury, Canada, which contain about 0.1% Rh. Iridium is usually obtained from native osmiridium (Ir 50%) or iridiosmium (Ir 70%) found chiefiy in Alaska as well as South Africa. 

Major portion of US reserves occur in Alaska, Colorado, Idaho, Nevada, New Mexico, and Utah. In Canada, British Columbia holds the richest reserves of molybdenum. Central and south American molybdenum reserves are found mainly in copper porphyry deposits. Chile s Chuquicamata and El Teniente deposits are two of the largest deposits in the world, and account for 85% of the country s molybdenum reserves. 

As a specific illustration reference may be drawn to molybdenum reserve scenario in the United States. The reserves are mainly grouped under five categories (i) primary, (ii) byproduct of copper ores, (iii) co-product of copper-molybdenum ores, (iv) by-product of tungsten ores, and (v) by-product of uranium ores. These have been presented and briefly elaborated in Table 1.14. It may finally be recorded by way of summary that the present day molybdenum sources in the world today seem to be principally of two main kinds first, the large-tonnage, low-grade, disseminated type of deposit in which molybdenite is the principal economic mineral second, the deposits in which molybdenite occurs as a by-product in... 

World molybdenum production has increased from about 90 metric tons in 1900 — half from Australia and Norway, half from the United States — to 136 tons in 1906, 1364 in 1932 (an order of magnitude increase in 26 years), 10,909 in 1946, and 91,000 tons in 1973. Through the years, molybdenum has been produced in about 30 countries. In 1973, about 60% of the worldwide production was from the United States, 15% from Canada, 15% from the U.S.S.R. and China combined, and 10% from other nations — Chile, Japan, Korea, Norway, and Mexico (King et al. 1973). By 1979, the United States produced about 62% of the world production of 103,000 metric tons, and exported about half, chiefly to western Europe and Japan other major producers in 1979 were Canada, Chile, and the U.S.S.R. (Kummer 1980). In the United States, only three mines in Colorado account for almost 70% of domestic production. Other active molybdenum mining sites in North America are in Arizona, Nevada, New Mexico, Utah, and California molybdenum reserves have also been proven in Idaho, Alaska, Pennsylvania, and British Columbia (Kummer 1980). About 65% of domestic molybdenum is recovered from ores rich in molybdenum the rest is a byproduct from ores of copper, tungsten, and uranium (Chappell et al. 1979). 

As with any mineral resource, an increase in price leads to an increase in exploration and an increase in reserves. To illustrate this point— in 2007 there was a spike in the price of uranium, which led to increased investment in exploration, with the result that world uranium resources increased by 15% in just 2 years. Compared to metals like copper and iron, which have been mined for millennia, uranium exploration is a relatively young field. Uranium can be expected to follow the resource expansion model of older commodities such as copper and iron. In the 1950s and 1960s, there was great doubt about future uranium resources but this is no longer the case, as large reserves have been discovered, and little exploration has been needed since the 1970s. 

This corresponds to 3% of the total copper reserves of the world. In the year 2000, production in its own mines was 21000 tonnes, i.e. less than 0.2% of the world production. 

Molybdenum is, as mentioned, present as molybdenite MoSj as an associated sulfide in copper deposits and as the principal sulfide in large low-grade porphyry molybdenum deposits. The reserve base amounts to about 11 milHon tonnes (counted as molybdenum) in the whole world, half of which is in the USA. These resources are enough to supply world needs for the foreseeable future. 

Cobalt reserves (known ore bodies that may be worked) in the world are estimated to 3.2 milKon tonnes (cobalt content) [30.4]. An estimate of the reserve base (known ore bodies that may be worked at some future time) gave 10 million tonnes, of which the DRC accounts for 25%. Most of this large reserve base is in nickel-bearing laterite deposits and in sedimentary copper deposits of DRC and Zambia. In addition millions of tonnes of speculative cobalt resources exist in manganese nodules on the ocean floor. 

---