Mining
Now a national historic site, this mill operated from 1913 to 1943, processing ore brought via the 22,000 foot Argo Tunnel. At the time it was built, it was the largest mill of its type in the world. It is now a tourist attraction.
Once one of two copper smelters owned by Asarco (the other is in Hayden, Arizona, closer to the company's mines in Arizona), El Paso once boasted an 828-foot-tall smokestack, and a 612-foot one, at their former 458-acre plant site. Operations were suspended in 1999, culminating in Asarco's filing...
One of the largest mining operations in the United States, the Mission Complex is a copper and silver mining network, with an underground mine and two open pits: the Mission pit, and the smaller, adjacent San Xavier North pit. The mine is operated by Asarco (which was purchased by Mexico's largest...
A major open pit copper and molybdenum mine and old company town in western Arizona. Operations have open and shut over the years, and ownership has changed, though when operational around 500 people are employed at the pit and the processing plants here. It was acquired by merger in 2007 by FCX, a...
Large open pit copper mine with over 17 billion gallons of wastewater contaminated from mining operations. The pit and much of the surrounding mines and smelting areas, including the Anaconda area and the 120-mile long Clark Fork River drainage area, have been designated as an EPA Superfund toxic...
The second largest electric-powered shovel in the world, now a museum. The 15-story coal scoop, which could be moved at a rate of 1/5 mile per hour on its set of eight tank treads, scooped the overburden off a seam of coal in a mine near Hallowell, Kansas, from 1963 to 1974. The mine, now reclaimed...
The electric shovel that operated at this coal mine was the largest single-bucket excavating machine ever built, and one of the largest mobile earth-moving machines in the world. It used as much electricity as 27,500 homes to scoop out 325 tons of material in each bite (220 cubic yards)....
This active mine is the second biggest open pit copper mine in the world, slightly smaller than the Chuquicamata pit in Chile. Digging started in 1904, and the hole is now half a mile deep and more than two miles wide. It is expected to be enlarged until the ore runs out sometime after the year...
A coal mine, where the coal is extracted and pulverized and mixed with water to form a slurry, which is then transported through a pipeline for 273 miles to the Mojave Generating Station, a power plant in Laughlin, Nevada. The 18-inch diameter pipe is currently the longest coal-slurry pipeline in...
Two coal mines in the nearby hills serve distant power plants. This silo is at the end of a 17-mile-long conveyor connecting to the Kayenta Mine on Black Mesa. From here it is loaded on to electric trains that take it 75 miles on a dedicated track to the Navajo Power Plant near Page. Power from...
Said to be the "world's largest single coal-mining complex," based on Arch Coal own statistics, the mine produces more than 10 percent of the U.S. coal supply annually.  Black Thunder extracted 31.6 million short tons from its open pit in 1994, and nearly 60 million tons in 2000. In total,...
A remote gold mining ghost town, north of Mono Lake, designated a state historic park in 1962. In its heyday, in 1879, it had a population of 10,000 and many of the original buildings remain, preserved in a state of "arrested decay". A sprawling ruin, in a remarkable landscape, that is only...
A large, now closed-down smelter for lead and zinc mining operations in the Coeur d'Alene region, called Bunker Hill, which is now one of the nation's largest Superfund toxic clean-up sites. Two large stacks at the smelter, one 715-feet high, were demolished in 1996, and the rest of the operation,...
Salt has been extracted from the dry lake bed since 1909, and continues to be mined today. The surface layer on much of the lake, which is three to seven feet thick, is removed in order to get at the salt, and is dumped in long rows of conical piles along the trenches. The Cargill Salt Company, the...
This 2,000-foot long tunnel, approximately seven feet in diameter, was chiseled through a mountain by William Henry Schmidt with hand tools and explosives. Begun in 1906 as a means of transporting ore from his mine to the processing site, Schmidt devoted the following 32 years of his life to...
A ghost town theme park, built out of the fairly extensive remains of an actual old silver mining town. Walter Knott, founder of the Knott's Berry Farm theme park, restored the ghost town, after taking much of it to Orange County, where he used it to begin his theme park there (near the present...
The California Portland Cement Company's Mojave Plant employs 150 people to extract limestone and produce cement at this 9,000 acre site. The plant opened in 1955, after a nine mile rail spur connecting the site to the main line at Mojave was built by the company. The plant has been expanded and...
The salt operations at the southern end of the San Francisco Bay are the largest, in area, in the country. Cargill (a privately held industrial conglomerate with 85,000 employees worldwide) owns all the salt operations on the bay, having bought the bay area's main salt producer, Leslie Salt, in...
This mine complex is among the largest in the state, employing over 1,600 people in 2000. Nearly 2 million ounces of gold is extracted here annually, valued at over $600 million. Its is one of three large mines in the state operated by the Newmont Mining Company, one of the pioneer mining companies...
The Carving Studio and Sculpture Center in West Rutland is an active art production site, located at a large, long-shuttered Vermont Marble production plant. Most of the buildings are leased to other companies, but the Carving Studio occupies a few of the more picturesque old ones, and installs...
The town of Concrete in the foothills of the northern Cascades once housed the largest concrete plants in the state. Nearly half of the concrete for the Grand Coulee Dam (the largest concrete structure in the world) came from here, as well as material for other Washington dam projects. The last...
The Cordero and Caballo Rojo mines were merged in 1997 to create one of the largest and most productive coal mines in the United States. Initially operated by Rio Tinto Energy America, the mine was purchased by Cloud Peak Energy in 2010. The operation spans 6,500 acres of Bureau of Land Management...
One of the largest mine tailings piles in the world: 7.4 billion cubic feet, the New Cornelia Tailings is often cited as the largest dam structure in the country, by volume (the tailings, waste material from the mining process, were heaped into a pile that created a holding structure for future...
A shut-down Kaiser iron mine, that once provided ore to Kaiser's Fontana steel works. A suburban-looking development, with over 100 houses built to house mine workers and their families, is virtually abandoned, making Eagle Mountain one of the more recently-formed ghost towns. There is also a...
One of six radon health mines in this part of Montana, which apparently are the only active radon health mines in the United States. The Earth Angel, a former gold mine, has the strongest concentration of radon gas, limiting users to 20 visits at a stretch (instead of the usual 30). Halfway down...
An inactive and well preserved coal mining town, with a museum to the industry located at the site. Part of the well-preserved look is due to the fact that many of the mining buildings were constructed as part of the set of the The Molly Maguires, a 1970 film about a labor-management dispute,...
The Phelps Dodge Mining Company's refinery in El Paso was once one of the largest refiners of electrolytic copper in the U.S.. The  plant, which during the 1950's employed as many as 750 people, was where copper was refined and formed into a continuous-cast rod, which would then be turned into...
The Elizabeth Mine, in South Strafford, was once the largest copper mine in the nation, and was still the largest in New England during WWII. Its production peaked in 1955, when it covered 850 acres (more than a square mile). When it closed in 1958, it was the last ore mine operating in Vermont. It...
Upper peninsula iron ore mine that has the capacity to produce eight million tons of iron ore pellets annually, one of the largest producers in the world. The operation is managed by the Cleveland-Cliffs Iron Company, which co-owns it with a number of large steel companies, as the ore pellet is...
An abandoned eco-land art site. In 1985 the artist Harriet Feigenbaum planted three circles of willow trees around a pond formed from coal dust runoff in this strip mining site. Currently maintained as a wetland wildlife preserve, but the art site is unkept.