WorldWide Drilling Resource

Alaska Miners Association Phone: 907-563-9229 Fax: 907-563-9225 ama@alaskaminers.org www.alaskaminers.org American Exploration and Mining Assn. Phone: 509-624-1158 Fax: 509-623-1241 info@miningamerica.org www.miningamerica.org WorldWide Drilling Resource ® is proud to be a member of these mining associations. Women in Mining 866-537-9694 wim@womeninmining.org www.womeninmining.org 55 WorldWide Drilling Resource ® MARCH 2015 Ancient Lake Bonneville by Harry W. Short Engineering Geologist Ancient Lake Bonneville developed 16,800 to 18,000 years ago. It spanned 19,750 square miles and was 346 miles long and 145 miles wide at its greatest extent. Bonneville reached a depth of 923 feet at its deepest point and covered much of present-day Utah and portions of Idaho and Nevada, covering an area about ten times larger than the current lake. The Great Salt Lake is the major remnant of Lake Bonneville. It is the largest saltwater lake in the Western Hemisphere and the fourth largest ter- minal lake in the world. The lake's size fluctuates substantially due to its shal- lowness. In 1963, it reached its lowest recorded level at 950 square miles; and in 1988, the surface area was at the historic high of 3300 square miles. In terms of surface area, it is the largest lake in the United States that is not part of the Great Lakes region. The lake developed in a closed basin with no outlet. The three rivers which feed the lake deposit around 1.1 million tons of minerals in the lake yearly. The water has a high salinity, is saltier than sea water, and its mineral content is constantly increasing. Called "America's Dead Sea", the lake provides habitat for millions of native birds, brine shrimp, shorebirds, and waterfowl. Rocks containing minute particles of salt, which is soluble in water, were carried into the lake to foster a major industry. This source is easily renewed by the continuous evaporation during high seasonal temperatures. An esti- mated 8 billion tons of salt has been precipitated in the lake over its lifetime. The harvesting of brine shrimp eggs has also become a multimillion dollar business in the Great Salt Lake. Many of the beaches contain oolitic (small, rounded spherical grains) sands, which are 0.3 millimeter in size. These small grains are layers of calcium carbonate that builds around small mineral grains or brine shrimp fecal pellets. Under microscopic view, the thin layers look like bands similar to volcanic geode layers. Mining in the Great Salt Lake has developed large solar evaporation salt ponds covering thousands of acres. So- dium chloride (common salt) is produced in the ponds and harvested mechanical- ly from the pond bottoms. The salt is washed, dried, and screened to produce different sizes and grades. It is also pressed into pellets for use in water softeners and formed into salt lick blocks with vitamins for livestock. Much of the salt is used locally to melt ice on the highways, and large quantities are shipped out of state for industrial use. Harvested salt is also sent out of state to companies which specialize in pro- cessing it into the table salt we all use. Potassium sulfate is also mined and made into fertilizer. Harry Harry Short may be contacted via e-mail at michele@ worldwidedrillingresource.com Bonneville Lake upper beach level in the background. "0",-" - 0 &' '" &) (*-. -&2"- )! )/( ", *# ' !"- "1 -"! &.- *'" +")",- , $ &.- &)$- ((",- ((", &.- &0",.",- " .&++&)$ . &'&2",- ' 1 &.- &+" &+"- *'. *) "".% / - * &'" &. *&) ,*! %*.( &' *( 111 &. *&) /-