For the second consecutive year, the value of U.S. mineral production increased according to the U.S. Geological Survey (USGS) which released its annual summary of mineral production.

According to the report, “Mineral Commodity Summaries 2012,” U.S. mineral production increased in 2011 with an estimated value of mineral raw materials mined of $74 billion. This is a 12 percent increase from $66 billion in 2010.

The estimated value of U.S. metal mine production last year was $37.1 billion, a 23 percent increase over 2010, while the value of industrial minerals mine production in 2011 was $36.9 billion, a 3 percent increase over 2010.

Gold remained the most valuable mineral at $12.2 billion in 2011, a 3 percent increase over 2010. The report found that 30 operations yielded more than 99 percent of U.S. gold with 24 producers producing commercial-grade refined gold.

Mine production of 15 mineral commodities was worth more than $1 billion each in the United States last year including (in order of value) gold, crushed stone, copper, iron ore, construction sand and gravel, cement, molybdenum concentrates, phosphate rock, lime, zinc, salt, clays, soda ash, silver, and industrial sand and gravel.

The report found that the U.S. remained 100 percent dependent on imports of 19 commodities and that overall more than one-half of U.S. consumption of 43 mineral commodities came from imports. In 2011 the U.S. was a net exporter of 18 mineral commodities, meaning more of those domestically produced mineral commodities were exported than imported.

Last year, 10 states each mined more than $2 billion of nonfuel mineral commodities (in descending order of value) including Nevada, Arizona, Minnesota, Utah, Alaska, Florida, California, Texas, Michigan, and Missouri. The combined mineral production of these state accounted for 62 percent of total U.S. output value.

The USGS also determined that the Defense Logistics Agency sold $94.4 million of excess mined materials from the National Defense Stockpile in fiscal year 2011.

Copper--U.S. mine production of copper in 2011 increased slightly to about 1 Mt (1.1 million st) and its value rose to $10 billion. Arizona, Utah, New Mexico, Nevada, and Montana-in descending order of production accounted for more than 99 percent of domestic mine productions.

Silver-In 2011, the U.S. mined 1,052 t (1,160 st) of silver with an estimated value of $1.27 billion. Silver was mined as a byproduct from 35 U.S. base- and precious-metal mines. World silver mine production increased to a new record of 21.5 kt (23,800 st) last year.

Iron ore-In 2011, mines in Michigan and Minnesota shipped 99 percent of the usable iron ore production in the United States, with an estimated value of $6 billion. Thirteen iron ore mines operated during the year with eight of those mines operated by three companies that accounted for virtually all of the production. The U.S. was estimated to have produced and consumed 2 percent of the world's iron ore output.

Lead-Six lead mines in Missouri, plus lead-producing mines in Alaska and Idaho yielded all U.S. lead production in 2011, valued at $918 million.

Molybdenum-U.S. mined production of molybdenum increased by 8 perent in 2011 to 64 kt (70,500 st). Identified resources of moly in the U.S. amounted to 5.4 Mt (5.9 million st), and in the rest of the world, about 14 Mt (15.4 million st).

Zinc-The value of zinc mined in the U.S. last year was $1.78 billion and was produced in four states at 13 mines operated by four companies.