R o s s G u i d aG e o l o g y 3 0 11 0 / 2 4 / 2 0 0 7G Y P S U M

Gypsum mining areas

Gypsum Mining in the United States of America

from: http://minerals.usgs.gov/minerals/pubs/mapdata/#map edited in Adobe Illustrator by Ross Guida

CaSO4·2H2O (Hydrous)CaSO4 (Anhydrous)

Chemical Formula

The largest application of gypsum is in forming building materials. Gypsum is used to make plaster products, drywall, sheetrock, and other types of wallboard. Some other uses include cement production, glass making, and fertilizers for agricultural purposes.

Applications Reserves of gypsum aren’t easily totaled since it is so abundant and most industrialized countries have large quantities of it. The USGS estimates the combined reserves of Brazil and the U.S. totaled about 2 billion tons in 2006. It’s pretty clear because of it’s abundance and new synthetic developments, we won’t be running out in the near future.

Reserves

Gypsum is processed by grounding the mined rock into powder with heavy machinery, heating the minerals to between 150 and 165 degrees Celsius. This removes 3/4 of the water. This ia now CaSo4*1/2H20, commonly called Plaster of Paris (hemi-hydrate plaster). It is then remoisted and it dries becoming harder than it was before.

Processing

Environmental problems with mining gypsum cause many people to worry. Since it is so close to the surface in some cases, open pit mining is used. When it isn’t, the rock is either blown away and then mined using open-pit mining or underground mining is used. Most of the time, tailings litter the landscape and rock formations are completely destroyed by explo-sives. However, with synthetic production, problems are being reduced. Gypsum is also reused in large quantities. 4 million tons of the 21 million produuced in 2006 were from recycled gypsum products.

Environmental Problems

Gypsum is a mineral sulfate that forms from the evaporation of salty seawater or lake water in tidal-�ats and narrow seas. It is found mainly in sedimentary layers in areas previously cov-ered in highly salinic water. When mined, overlying sedimentary rocks are blasted away or drilled through and the gypsum-rich layer is mined down to its base. Recent discoveries and innovations now allow gypsum to be made synthetically. In 2006 24% of the U.S. gypsum production was synthetic. It is made mainly by using byproducts from reducing pollution in coal-powered power plants. It is becoming more environmentally friendly because it reduces waste from mining in a natural environment and if used with re-cycled paper, the resources are all being reused.

Found naturally as selenite, satin spar, gypsite, and massive gypsumWhere Is Gypsum Found and How is it Formed

21.2 million tons produced in the U.S. in 2006. -Total value of $159 million -91% used in wallboard production - -45 mines in 14 states4 million tons recycled in the U.S. alone 119 million tons produced worldwide

37.2 mill. sq. ft. made

Some Interesting Facts

Gypsum mine in Colorado

Underground gypsum mine

Drywall and sheetrockin a new home

Gypsum powder afterheating the hydrous

mineralGypsum plant in Britainwww.visitcumbria.com/gypsum-5583b.jpg

Gypsum, Colorado