Historical Uses Since 4000 BCE Cinnabar used for the preservation of human bones including Egyptians Since Egyptian/Roman times cinnabar used as paint pigment, cosmetic, pottery glaze, anti fouling on ships, red ink. Romans: Extraction of elemental Hg by distillation and amalgamation with gold Middle ages: Hg amalgamation used in alchemy and early chemistry leading to the discovery of 22 elements Medicinal use since 460 BCE (Hippocrates) and since 16 th century as a cure for syphilis, and as a diuretic, antiseptic, contraceptive Still used in dental amalgam, preservative in flu vaccines (Thimerosal), herbal remedies
Industrial Use Chor-alkali process: Hg cathode in electrolytic production of NaOH and Cl from NaCl Pulp and paper industry (production of Cl) Insecticides, herbicides, fungicides, bactericides; some with very toxic alkyl mercury Pendulum clocks Thermometers, barometers, blood pressure gages Electronics industry Vacuum pumps Liquid mirror telescope (rotating mercury produces a perfect parabola) Switches, thermostats, florescent lamps, batteries, computers Extraction of gold and silver
Toxicity Knowledge of toxicity from miners. Roman slaves and Spanish convicts had an average life expectancy in the Hg mines of 3 years Causes loss of teeth, tremors, loss of strength, psychological problems. Mad Hatter disease due to use of mercuric nitrate in felting of fur for hats Methyl mercury extremely toxic
Mining Cinnabar mined at Amaden Spain since 430 BCE. HgS heated to release elemental Hg as a gas which is condensed
Almeda Hg Mine Spain Continuous production for over 2000 years since Romans Total production ~ 250,000 tons Hg, 1/3 of entire world production During the Arab domination of Spain, The Moors operated the mine during between the 8th and 13th centuries. Hg used in medicine and alchemy. 12th century: mine 450 m deep with >1,000 workers. 13th century Almadén was recaptured and held by Spanish Christians. 16th century: amalgamation to extract gold and the silver discovered causing major expansion of mine. 16th and 17th centuries, most Hg was sent to Seville for American gold extraction. From 17th century, production reduced due to exhaustion of near surface ore. January 1755, a fire burned in the mines for >2 years, killing many people. Early 19th century, labor problems due to the bad Spanish economy. 1835 mercury was auctioned in London and mine economy improved. 1916, special Council created for operation of the mines; technical and safety improvements introduced. 1941 After the Spanish Civil War, record production; 82,000 Hg flasks. 1981 the Spanish government created the company Minas de Almadén y Arrayanes, S.A. to operate the mine.
Environmental Issues related to Hg Mining Secondary minerals –In roasted ore (calcines) 10-1000 ppm Hg, mostly metacinnabar –Forming in condensers, 100-10,000 ppm Hg, must be removed by hand and discarded in tailings Waste Rocks and low grade ore Emissions: adjacent soils have 10s ppm Hg Runoff from mine site and waste dumps are often adjacent to streams Wind blown particles, fine particles of calcine have high Hg Mine drainage: open pit and underground
Rathburn –Petray Hg Mine, Cashe Creek, CA Worked prior to 1892, greatest activity between 1892 and 1893 for use in gold mining operations in California. Minor production in 1960's and 1970's. Hg-bearing material exposed in cuts, slopes, open pits, mine waste piles, and storm water retention ponds. Ash from a brick retort contains elevated levels of mercury. Waste piles contain approximately 101,500 m 3 Hg-bearing material. Surface water runoff during storm events erodes waste and tailings piles, overflows retention ponds, and transports Hg-laden sediment into tributaries of Cashe Creek. Contributes 6.8 to 53.1 kg/year Hg