Zinc mining

Open-pit zinc mining is not common, since most mines ate below the surface. The Kidd Creek Mine in Ontario, Canada, is a combination open-pit—underground mine. It is one of the richest deposits in the world with an estimated 62.5 x 10 t grading 7.08% zinc, 1.33% copper, and 151 g silver (14). Underground mining methods include room-and-pdlar, shrinkage, cut-and-fill, and square set. In the United States, ca 20 mines account for more than 98% of zinc production. 

Country Mine Slab zinc Mine Slab zinc Mine Slab zinc Mine Slab zinc... 

The level of natural versus man-made emissions to the environment are of a similar magnitude. SoH erosion is the major contributor of natural emissions with zinc mining, zinc production facHities, iron and steel production, corrosion of galvanized stmctures, coal and fuel combustion, waste disposal and incineration, and the use of zinc fertilizers and pesticides being the principal anthropogenic contributors. 

Hazards of Production. In most zinc mines, zinc is present as the sulfide and coexists with other minerals, especiaHy lead, copper, and cadmium. Therefore, the escape of zinc from mines and mills is accompanied by these other often more toxic materials. Mining and concentrating, usuaHy by flotations, does not present any unusual hazards to personnel. Atmospheric poHution is of Httle consequence at mine sites, but considerable effort is required to flocculate and settle fine ore particles, which would find their way into receiving waters. 

Particulate emissions are controHed mainly through venting, baghouses and water scmbbers. Atmospheric zinc loss is estimated at 100 g/1 or zinc mines, mostly from handling dry ore and concentrate and wind erosion of tailing pHes. Sulfur dioxide emissions have been reduced by installing double absorption acid plants and improved containment of dilute gases. 

Schwabe, J.W.R., Klug, A. Zinc mining for protein domains. Nature Struct. Biol. 1 345-350, 1994. 

Cadmium is an extremely toxic metal that finds its way into the aqueous environment as a result of some human activities. A major cause of cadmium pollution is zinc mining and processing, because natural deposits of ZnS ores usually also contain CdS. During the processing of these ores, highly insoluble cadmium sulfide ( sp = 7.9 X 10 ) maybe converted into considerably less insoluble cadmium hydroxide (.E p — 7.2 X 10" ). What mass of Cd (OH)2 will dissolve in l.OOx lO L of an aqueous solution ... 

Garcia, M. A. Mejias, A. Martin, D. Diaz, G. Upcoming zinc mine projects the key for success is ZINCEX solvent extraction. Lead-Zinc 2000, Proceedings of the Lead-Zinc 2000 Symposium, Pittsburgh, PA, United States, Oct. 22-25, 2000, 751-761. 

Saunders, R.L. and J.B. Sprague. 1967. Effects of copper-zinc mining pollution on a spawning migration of... 

Otters (Lutra lutra) were found only on a single unpolluted tributary of a river system contaminated by zinc mine drainage waste, suggesting that a contaminated food supply may be responsible for avoiding otherwise suitable habitat (Mason and Macdonald 1988). 

Marine mammals collected near heavily urbanized or industrialized areas or near zinc pollution point sources usually had elevated zinc concentrations when compared to individuals of the same species and of similar age from relatively pristine environments (Eisler 1984). Zinc concentrations in tissues of the ringed seal (Phoca hispida) were essentially the same in animals near a lead-zinc mine and in those of a distant reference site, although lead and selenium burdens were elevated in the vicinity... 

Grey field slug, Deroceras reticulatum, near lead-zinc mine Digestive gland 3968 DW 6... 

Greville, R.W. and A.J. Morgan. 1989. Concentrations of metals (Cu, Pb, Cd, Zn, Ca) in six species of British terrestrial gastropods near a disused lead and zinc mine. Jour. Molluscan Stud. 55 31-36. 

Open manometers, 20 646—647 Open-mold process, for unsaturated polyesters, 20 116-117 Open-mold processing, 19 558 Open-pit zinc mining, 26 557 Open reading frames (ORFs), 26 480, 481 with yeasts, 26 491—492 Open system... 

Table 10.15 Comparisons of flotation results of OPCF and traditional flotation in concentrator of Xitieshan lead-zinc mine...

The flotation separation of galena, sphalerite and pyrite in Fankou lead-zinc mine is very complicated because these three minerals are finely disseminated. The OPCF technology is also successfully applied to this plant to separate these three minerals. Here, pH is modified to 12 by lime and pulp potential is maintained as less than 170 mV. The mixture of xanthate and DDTC is used as a collector in flotation of galena. CUSO4 is used as a collector in the flotation of sphalerite. The principal flowsheet of OPCF for flotation separation of Fankou lead-zinc ore is given in Fig. 10.20. The comparison of results of plant production for OPCF and old flowsheet is listed in Table 10.16. It can be seen that the OPCF technique... 

Takijima Y, Katsumi F. 1973. Cadmium contamination of soils and rice plants caused by zinc mining. I. Production of high cadmium rice on the paddy fields in lower reaches of the mine station. Soil Science and Plant Nutrition 19 29-38. 

Some Famous American Zinc Mines. In 1810 Dr. Archibald Bruce analyzed a new orange-red mineral from Fianklin Furnace, Sussex County, New Jersey, and found it to be zinc oxide containing a little manganese. This mineral is now known as zincite (100,101,102). 

A month later Boisbaudran performed in Wurtz s laboratory in Paris, in the presence of the chemistry section of the Institute, a series of experiments to prove that gallium, the metal he had discovered and named in honor of France, is a true element. In order that he might attempt to isolate the metal, the technical zinc-mining societies known as La Vieille Montagne and La Nouvelle Montagne presented him with a quantity of gallium-containing zinc minerals. 

DuPont Works, built in 1909 at the village of DuPont, Washington, near Tacoma. It fronts Puget Sound for low-cost shipments to Alaska, Hawaii, the Philippines and some west coast South American ports. The most important outlet of this plant has been, however, to the copper, silver and zinc mines of Idaho and Montana. Expls for quarrying, lumbering, land clearing and seismic prospecting, were also important items... 

Alison Dickson is a metallurgist at Polaris, the world s northernmost mine. Polaris is located on Little Cornwallis Island in Nunavut. It is a lead and zinc mine, operated by Cominco Ltd., the world s largest producer of zinc concentrate. 

Cadmium is found in low concentrations in most soils and waters. It is produced as a by-product of zinc and lead mining and smeltering. Industrial use of cadmium has led to a dramatic increase in environmental problems caused by this element. Cadmium is used in semiconductors, nickel-cadmium batteries, electroplating, polyvinyl chloride (PVC) manufacturing, and control rods for nuclear reactors. The most important sources for aquatic contamination are active and inactive lead-zinc mines, land application of sewage sludge, zinc-cadmium smelters, effluents from plastic and steel production, and wastewaters from the production of nickel-cadmium batteries and electroplating (Zuiderveen, 1994). 

Itai-itai disease was identified in residents of the Jinzu River Basin in Japan in the mid-1940s. A lead and zinc mine polluted the river with high levels of Cd. The river water was used in the irrigation of rice fields and for drinking water. People affected by the disease suffered severe kidney dysfunction and painful skeletal symptoms. In the worst cases, bones would break from slight pressure, even from simply coughing. It is important to note that the worst cases were presented in... 

Dangerous levels of human exposure from diet have occurred, most notably in Fuchu, in northern Japan where rice was eaten that was contaminated with cadmium derived from an old zinc mine and present in soil and water. Low calcium intake and vitamin D deficiency may also have been factors. The victims suffered from brittle bones, and it became known as itai-itai disease from the Japanese for ouch-ouch (see box). The village of Shipham in Somerset was, similarly, found to have very high levels of cadmium in the soil, which also derived from an old zinc mine. 

Mexico, the world s leading producer of silver since the Spanish conquest, obtains virtually its entire silver production from lead—zinc mines in the central cordillera. Mexico retained its dominance in silver production until the discovery of the Comstock Lode in Nevada in 1859. Discoveries in Colorado, Arizona, and Montana placed the United States as the world s top silver producer from 1871 until 1900. As these mines played out, Mexico s vast resources returned it to its former position of dominance. 

In the Commonwealth of Independent States (CIS, formerly the USSR), nearly 50% of the CIS production comes from Kazakhstan. Silver is produced from the lead—zinc mines at Ostkamen, Shymkent, and Leninogorsk (ca 1000 t) and also in Russia s Far East, where it is a by-product of the tin deposits near Khabarovsk, and of the copper and gold deposits in the Ural Mountains. 

U.S. silver production from 1985 to 1994 averaged 1588 t/yr. Less than one quarter of this output comes from silver mine districts, however. About half is as by-product of gold mines about one quarter comes from copper and lead—zinc mines. The silver production in Mexico from 1985 to 1994 averaged 2256 t/yr, and Pern, at the southern extremity of the cordillera, where silver is a by-product of copper and lead—zinc mines, averaged 1810 t/yr. 

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