Juneau mining district facts for kids
Quick facts for kids
Juneau mining district
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Alaska Mining District
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 Juneau mining district
Location in Alaska
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The Juneau mining district is an important area in Alaska, USA, known for its gold mines. It's located near the city of Juneau.
In 1880, a local leader named Chief Kowee showed two prospectors, Joe Juneau and Richard Harris, where to find gold. This was in a place now called Gold Creek in Silver Bow Basin. The city of Juneau was started there that same year.
This discovery led to the Juneau gold rush. Many mines were built, both for gold found in riverbeds (placer gold) and gold found in rock veins (lode mines). The biggest early mines were the Treadwell complex and the AJ (Alaska Juneau) lode mine. The area was perfect for mining because of its steep, wet, and forested mountains. These provided water power, easy transport, and wood for building. This meant they could mine even low-grade gold that might not be worth it elsewhere.
The Treadwell complex started in 1881. At first, miners washed gold from the surface. Later, they dug underground. By 1883, they had a five-stamp mill to crush ore. In the mid-1910s, Treadwell was very advanced. It had 960 stamps grinding ore and tunnels reaching deep under the sea. Up to 2,000 people worked there. But in 1917, a part of the mine collapsed, and sea water flooded the tunnels. All mining stopped by 1922.
As Treadwell mines closed, the AJ (Alaska Juneau) mine became more important. After some tough years, it became very successful in the mid-1920s. With 600 workers, it set new production records. It was the main economic driver for Juneau. In the 1930s, with 1,000 workers, it helped Juneau during the Great Depression. But the economic pressures of World War II caused the AJ mine to close in 1944. This marked the end of large-scale mining in Juneau.
Even though these big mines are closed, one of the power plants built for the AJ mine was still used as late as 2010. Most of the old Treadwell buildings are gone due to fires and time. The AJ mine buildings were burned by vandals, so there's not much left for visitors to see today.
The Juneau mining district covers a large area. It stretches from the Canada–US border to Lynn Canal, Admiralty Island, and Frederick Sound. This district has produced over 7 million ounces of lode gold and 80,000 ounces of placer gold.
Contents
History of Gold Mining
Early Discoveries (1869–1921)
The first gold in Alaska was found in 1869 at Powers Creek and Windham Bay. This led to the start of gold production in the state. The Treadwell and Alaska Juneau companies were key in setting up large mining operations. At first, they focused on gold found in loose deposits. But in the early 1880s, they shifted to finding gold in rock veins (lode deposits).
In 1881, the Treadwell complex built its first stamp mills in Silver Bow Basin. This helped increase gold production, especially from lode mines. John Treadwell, a Canadian gold miner, owned and ran the Treadwell gold mine. He was a pioneer in mining low-grade gold on a large scale. His advanced methods boosted the economy of this wild area. His four mines formed the biggest complex in the world at that time. Treadwell's mines truly "put Juneau on the map."
The Alaska Mill and Mining Company started in May 1882. They experimented with a five-stamp mill, which proved profitable. The company then grew, adding a 120-stamp mill in 1883 and another in 1887. The Treadwell Complex had four mines and five mills. They produced about US$70 million worth of gold.
Between 1890 and 1915, many smaller mines also opened. These included the Sumdum Chief, Crystal, Comet, Jualin, Silver Queen, and Eagle River mines. The Treadwell complex reached a peak, processing 5,000 short tons of ore every day. However, by 1917, the smaller mines closed. Treadwell also had to stop operations suddenly due to a major accident. Their mines flooded when a cave-in allowed sea water to rush in.
After this, the old Perseverance Mine was restarted as the Alaska Gastineau Co. They used new methods, like ball mills, which had worked well for copper mining. Their production increased for a while but then declined due to problems. They closed their mines in 1921. By the time Treadwell stopped, it had produced about 3.1 million ounces of gold.
Alaska Juneau Mine (1915–1944)
The Alaska Juneau Mine faced some early challenges but then became very successful. They also used the new ball mill technique for grinding ore. This allowed them to process 12,000 short tons of ore per day. They reported good profits from their gold extraction.
Between 1930 and the early 1940s, the Alaska Juneau Mine became the largest gold mine in the world. It also produced a lot of lead. However, World War II, rising costs, and a fixed price for gold made it hard to keep operating. The mine closed in 1944. Overall, it produced 2.9 million troy ounces of gold, 1.9 million ounces of silver, and 40 million pounds of lead.
Modern Interest (1970–Present)
Since the late 1970s, gold prices have gone up. This led to new interest in the old mining areas. People looked at old mines again, but not much happened until 1985. That year, efforts began to restart the great Alaska Juneau Mine.
From 1880 to 1983, the mines in the Juneau Gold Belt produced gold, silver, and lead worth $157,000,000. This included 6.7 million ounces of gold, 3.1 million ounces of silver, and 45 million pounds of lead.
Since 1985, many mining companies are looking into restarting some of the old mines. The Alaska Mining Centre studied the old mines as part of a program to assess mineral lands. This study looked at about 85 mines and collected many samples to see future possibilities.
Major Mines
Treadwell Mine
A prospector known as "French Pete" found gold on Douglas Island, which is across from Juneau. A group led by John Treadwell bought these claims and other gold-rich land. The mine and mill complex they built produced more than 3 million ounces of gold before it closed in 1922.
Kensington & Jualin Mines
The Kensington hardrock mine is an underground mine about 45 miles (72 km) north of Juneau. It is located within the City and Borough of Juneau and the Tongass National Forest.
Mining and ore production happened at the Kensington mine from 1897 to 1938. The nearby Jualin mine was found in 1895 and operated from 1896 to 1928. Together, these mines produced 40,513 ounces of gold from 75,208 tons of ore.
Interest in these mines grew again in the 1980s and 1990s. The Kensington Project is now getting its final permits. The plan is for this underground mine to produce about 2,000 tons of ore per day for about 10 years. The project now includes both the Kensington and Jualin areas.
The proposed mine, its roads, and waste disposal areas are on federal land managed by the U.S. Forest Service, state tidelands, and private land. The project expects to hire 300 to 400 people for construction and 225 full-time workers to run the mine. The mining process will use froth flotation. This involves crushing the ore, then mixing it with water and chemicals that attach to the gold. The gold then floats to the surface and is collected.
In 2009, the Supreme Court of the United States made a decision about the mine. They ruled that the Army Corps of Engineers could allow mine waste, a mix of crushed rock and water, to be put into Lower Slate Lake. This lake is 23 acres (93,000 m2) big and up to 50 feet (15 m) deep. The Environmental Protection Agency also allowed treated water from the lake to be discharged.
While waste is put into the lake, surface water is sent around it. A dam will be built to hold water as the lake fills with waste. The lake area will grow to 50 acres (200,000 m2) over the project's life. When the project ends, the lake bottom will be covered with natural material, and the lake will be restocked with fish. The company said that using the lake for waste was better than building tailing ponds, which would have harmed wetlands. They also said enlarging the lake would create new wetlands.
Environmental groups argued that this decision was made possible by a rule change in 2002. This change allowed waste to be considered "fill material" that could be put into waters. Before this, "fill material" did not include waste.
