A metallic mineral has a distinctive, shiny, metallic luster. Metallic minerals such as gold and silver are also economic minerals. They are valued as beautiful collectible pieces and also for their widespread industrial use. The early history of the state of Colorado parallels the history of metal mining and is directly tied to the first significant and documented discovery of gold in the summer of 1858. A party of prospectors discovered placer gold in stream gravel at what is now downtown Denver, near the confluence of the Cherry Creek and South Platte Rivers (Auraria). This discovery led to the first Colorado gold rush. “Pike’s Peak or Bust” was emblazoned on many of the ox-drawn wagons carrying optimistic prospectors across the Great Plains to the Rocky Mountains of Colorado.
At various times throughout its history, Colorado has been the leading U.S. producer of gold, silver, molybdenum, lead, zinc, uranium, and tungsten. Other metals that have been mined in Colorado include copper, tin, vanadium, iron, beryllium, lithium, rare earth elements, thorium, tantalum, and manganese.
Total Metallic Mineral Production through 1953
Gold 1858-1953 39,937,129 fine ounces
Silver 1858-1953 750,098,322 fine ounces
Copper 1868-1953 640,702,430 pounds
Lead 1869-1953 5,303,666,583 pounds
Zinc 1895-1953 3,326,405,985 pounds
Base metals that have been historically mined in Colorado include lead, zinc and copper. There is no current production of these metals although activity will likely increase, as the price of the base metals continues to rise. Copper in particular has soared, the price reaching $4.00 per pound in November of 2010, but has since slowly declined to about $2.50 per pound as of January 2015. In comparison, lead and zinc are hovering around $1.00 per pound.
Most copper is used in construction (49 percent), electric and electronic products (20 percent), transportation equipment (11 percent); consumer and general products (11 percent); and industrial machinery and equipment (9 percent). The current need for copper conductors in alternative (“green”) energy is significant.
Colorado ranks fourth in the U.S. in gold production behind Nevada, Alaska, and Utah. Total Colorado gold production in 2011 was 265,000 ounces, for a net value of $318 million.
The Cripple Creek and Victor Mine in Teller County (pictured at right) is the top Colorado producer of gold and silver. Additional small amounts of gold were probably produced from small placer (gravel) or lode mines that do not publicly disclose production figures.
Gold is used mainly in jewelry, coins, and bullion. However, 10 to 20 percent of gold is used in electronics, dentistry, and industrial applications. Gold has superior electrical conductivity and corrosion resistance that makes it important in computer hardware, communications equipment, spacecraft, and jet engines.
Lead is one of the family of elements called heavy metals. It is used in building construction, manufacture of lead-acid batteries, bullets, weights, solder, pewters, fusible alloys, and radiation shielding. It has the highest atomic number (82) of all the stable elements.
A little known fact about lead is that it plays a critical role in smelter operations. Without lead it would be nearly impossible to recover many of the more valuable metals in metallic ores.
Lead is a natural part of many metallic ores, often found in combination with zinc and copper. Colorado has produced billions of pounds of lead during its long mining history.
Colorado is the leading producer of molybdenum metal in the U.S.
Climax molybdenum mine at Fremont Pass, the largest primary molybdenum mine in the world. Photo by V. Matthews.
The Henderson Mine in Clear Creek County is the nation’s largest primary molybdenum mine; the mine produced 35 million pounds of molybdenum in 2008. The mine lies in the Front Range, just west of Empire. The Climax Mine near Leadville began reopening in 2008, but when the price of molybdenum dropped from more than $30 per pound less than $10 per pound in a few weeks, the reopening was suspended. At least two additional major deposits in Colorado are known; the Lucky Jack deposit in Gunnison County and a large deposit at the old mining town of Rico in Dolores County.
Molybdenum is used primarily as an alloy agent in stainless steel, other specialty steels and cast iron. As an alloying agent, molybdenum provides hardness and durability to steel, especially at high temperatures, and imparts corrosion resistance, particularly to salt corrosion. It also increases the toughness and weldability of steel. The metal is used in electrodes for glass furnaces, in rocket engine components, liquid metal heat exchangers, in the superstructure of large buildings, and as a heat-resistant lubricant for machining.
Molybdenum has been shown to break down sulfite toxin accumulations in the body and may prevent dental cavities. Lima beans, liver, milk, peas, spinach and a variety of other dark green leafy vegetables contain molybdenum.
The dominant non-metallurgical use is in catalysts. LCD computer and television screens have a very thin layer of molybdenum on the glass as a base on which transistors and circuit wires are laid. Because molybdenum easily bonds to glass and conducts electricity and heat efficiently, it improves device performance. Molybdenum also plays a role in renewable energy technology, including solar and wind power. For example, a new type of solar panel made of copper-indium-gallium-selenide (CIGS)cells uses molybdenum—a thin layer near the bottom of each cell helps transfer the generated electricity to circuits external to the panel.
Silver is currently produced in Colorado as a byproduct of gold mining at the Cripple Creek and Victor Mine and the Cash Mine. The value of silver production is very small compared to that of gold because of the price differential between the two noble metals. In 2007, the Cripple Creek and Victor Mines produced more than 89,000 ounces of silver worth $1,193,522. The Cash Mine in Boulder County produced 4587 ounces in 2007.
Silver has the whitest color, the highest optical reflectivity, and the highest thermal and electrical conductivity of all metals. These properties give silver importance in such uses as mirrors, electrical and electronic components. The primary industrial use of silver was formerly in photography because of the photosensitivity of silver halides. The antibacterial characteristics of the metal are being exploited by the use of silver woven with fabric for odor-repellent clothing and antibacterial blankets for use by the military.
Uranium was reportedly identified in the yellow mineral carnotite in southwestern Colorado in the early 1900s and was reportedly first mined in an area on Roc Creek near what is the post office of the town Uranium. Our 1921 Bulletin-16 discusses these early mining activities.
In 1955, it was found and historically mined in an area identified as the Marshall Pass Uranium District located in Saguache County/southern Gunnison County and the Cochetopa Uranium District located in northwestern Saguache County about 20 miles southeast of Gunnison. The associated mines are discussed in RS-44 Geology and Mineral Resources of Saguache County, Colorado. More than 2 million pounds have been mined from one mine alone.
Uranium was also mined in Fremont, Jefferson, Moffat, Teller, and Weld counties as illustrated in CGS MS-11, Map of Colorado Uranium and Vanadium Mining and Milling Activities.
Zinc is the 4th most commonly used metal in the world, after iron, aluminum, and copper. It is primarily used in anti-corrosion applications, and is an essential trace element necessary for human, plant, and bacterial health. Zinc is most commonly mined from an ore called sphalerite, a sulfide nearly always found in conjunction with sulfides of copper, lead, and iron. Copper is combined with 3% to 45% zinc to make brass alloys.
Historically, Colorado was a major producer of zinc in the United States, however, production has declined and the primary producers in the United States are now Tennessee and Missouri.