Lead Ore Deposit
Galena deposits often contain significant amounts of silver as included silver sulfide mineral phases or as limited solid solution within the galena structure. These argentiferous galenas have long been the most important ore of silver in mining. In addition zinc, cadmium, antimony, arsenic and bismuth also occur in variable amounts in lead ores. Selenium substitutes for sulfur in the structure constituting a solid solution series. The lead telluride mineral altaite has the same crystal structure as galena. Within the weathering or oxidation zone galena alters to anglesite (lead sulfate) or cerussite (lead carbonate). Galena exposed to acid mine drainage can be oxidized to anglesite by naturally occurring bacteria and archaea, in a process similar to bioleaching.
Galena deposits are found worldwide in various environments. Noted deposits include those at Freiberg, Saxony; Cornwall, The Mendips, Somerset, Derbyshire, and Cumberland, England; the Madan, Smolyan Province, Rhodope Mountains, Bulgaria; the Sullivan Mine of British Columbia; Broken Hill, Australia and the ancient mines of Sardinia. Galena also occurs at Mount Hermon in Northern Israel. In the United States, it occurs most notably in the Mississippi Valley type deposits of the Lead Belt in southeastern Missouri, and in the Driftless Area of Illinois, Iowa and Wisconsin. The economic importance of galena to the early history of the Driftless Area was so great that one of the towns in the region was named Galena, Illinois.
Galena also was a major mineral of the zinc-lead mines of the tri-state district around Joplin in southwestern Missouri and the adjoining areas of Kansas and Oklahoma. Galena is also an important ore mineral in the silver mining regions of Colorado, Idaho, Utah and Montana. Of the latter, the Coeur d'Alene district of northern Idaho was most prominent.
Galena is the official state mineral of the U.S. states of Missouri and Wisconsin; the former mining town of Galena, Kansas takes its name from deposits of this mineral.
The largest documented crystal of galena is composite cubo-octahedra from Great Laxey Mine, Isle of Man, U.K. measuring 25 cm × 25 cm × 25 cm.
Read more about this topic: Galena
Famous quotes containing the words lead and/or deposit:
““Yet let him keep the rest,
But keep them with repining restlessness:
Let him be rich and weary, that at least,
If goodness lead him not, yet weariness
May toss him to My breast.””
—George Herbert (1593–1633)
“A real life, a life that leaves a deposit in the shape of something alive.... It’s difficult to say what makes a life a real life.... You could also say it depends on a person being identical with himself.”
—Max Frisch (1911–1991)