Photographs courtesy San Juan Juan County Historical Society. All Rights Reserved.
© San Juan Publishing Group, Inc. All Rights Reserved.
MILLIONS OF YEARS
AGO, colossal volcanic forces spawned a nascent mountain range, known
today as the San Juans. The last throes of this mighty volcanism
shot hot mineral juices through cracks in the solidified volcanic rock.
The molten liquid crystallized into the network of richly
mineralized veins that riddle these mountains today.
As a result of this primordial violence, San Juan County developed into a major gold and silver mining district. By the late 19th century, the region was bustling with four railroads transporting riches from the high mountain camps. The gold and silver didn’t come out of the mountains in tidy stacks of bullion, however. Even the most legendary high-grade ores yielded only ounces of gold per ton.
Finding the ore and digging it out of the mountains was therefore only the first step of the intricate, arduous process of getting the metals to market. Mills played the next vital role, separating and concentrating the valuable stuff (gold, silver, and in exponentially greater quantities, the base metals copper, lead, and zinc) from completely worthless “gangue” minerals like quartz and pyrite that nobody wanted.
Once, the region was dotted with these precious metals mills. Now only a handful of historic mills remain, and most are in various stages of ruin.
The Mayflower Mill (aka
Shenandoah-Dives Mill), immediately north of Silverton, is a shining
exception to this sad state of affairs. It was the last major
accomplishment of Charles A. Chase, a metallurgist and successful
mining man. Due to the Depression in the 1930s, most mining companies
throughout the West were demolishing mills and other mine structures to reduce tax and
insurance liabilities. But Chase gambled that base metals extracted
from the ore could carry the costs of the mining operations, and he
targeted profit from winning the gold and silver.
Chase designed the Mayflower as a state-of-the-art facility, radically improving productivity and efficiency, while also incorporating environmental innovations. Instead of dumping waste material and toxic residue into the rivers as had been historically done, Chase pioneered holding, or tailings ponds, to contain the mill’s waste material.
Because of its almost continuous use since it was built, the mill has always been kept in good repair. It was connected with the Shenandoah Mine across the Animas River canyon by a stunning, state-of-the-art, 10,000 foot aerial tram—the only tram constructed with metal towers in the San Juans. Using gravity for power, the tram carried the ore (and often commuting miners) from the mine down to the mill. Miners could then hitch a ride back up to work in an empty ore bucket.
Once at
the mill, all of the ore was dumped into one central point—where it was
crushed then ground into very fine pieces about the size of a grain of
salt. Next, through a “flotation process” consisting of various
wonderful contraptions and alchemistic potions, each grain was
separated according to its physical characteristics and routed to other
destinations in the mill. Coarse, free-gold (tempting to the
sticky-fingered) was taken away early in the process to make gold
concentrates, while other minerals went off in various directions to be
separated from the waste.
From the mill, mineral concentrates were shipped to smelters for further processing and purification, while “gold sponge” (a lustrous substance, about 80% pure) was carried away by hand and shipped out of the county by U.S. mail (insured of course) most of it to be purchased by a bullion buyer, like Handy and Harmon in California. There it would finally be rendered into “9999 fine” gold bullion that would do Fort Knox proud.
In recent decades, it was ore from the Sunnyside Mine, about eight miles to the northwest of Silverton up Cement Creek, which fed the Mayflower Mill. But in 1991, the region’s gold-mining era ended when the 125-year-old Sunnyside, the last, large mine in San Juan County, ceased operations. Low base-metal prices and diminishing traces of gold and silver, coupled with new and rising costs of getting it, left the mine without profitable ore. In its colorful lifetime, over 900,000 ounces of gold were produced, millions of ounces of silver, and tons of base metals.
Sunnyside
Gold Corporation, the mine’s operator, immediately began implementing
the reclamation plan required by its mining permit, calling for the
Mayflower Mill to be torn down and the site reclaimed. But because
of the Mayflower’s historical significance to the region,
Sunnyside Gold was persuaded to donate the venerable mill to the San
Juan County Historical Society.
In 2000, the Mill and the tailings ponds were designated a National Historic Landmark, one of only twenty in the State of Colorado. Grant funding has recently allowed the structure’s integrity to be assessed and documented in preparation for much-needed stabilization and repairs. The Society has applied for a “Save America’s Treasures” grant to implement the plan.
Today the Historical Society runs tours of the Mayflower Mill throughout the summer season. All of the machinery remains as it was in August, 1991, when the Sunnyside shut down, the final whistle sounded, and the Mayflower Mill closed forever. Come have a look!
As a result of this primordial violence, San Juan County developed into a major gold and silver mining district. By the late 19th century, the region was bustling with four railroads transporting riches from the high mountain camps. The gold and silver didn’t come out of the mountains in tidy stacks of bullion, however. Even the most legendary high-grade ores yielded only ounces of gold per ton.
Finding the ore and digging it out of the mountains was therefore only the first step of the intricate, arduous process of getting the metals to market. Mills played the next vital role, separating and concentrating the valuable stuff (gold, silver, and in exponentially greater quantities, the base metals copper, lead, and zinc) from completely worthless “gangue” minerals like quartz and pyrite that nobody wanted.
Once, the region was dotted with these precious metals mills. Now only a handful of historic mills remain, and most are in various stages of ruin.
The Mayflower Mill (aka
Shenandoah-Dives Mill), immediately north of Silverton, is a shining
exception to this sad state of affairs. It was the last major
accomplishment of Charles A. Chase, a metallurgist and successful
mining man. Due to the Depression in the 1930s, most mining companies
throughout the West were demolishing mills and other mine structures to reduce tax and
insurance liabilities. But Chase gambled that base metals extracted
from the ore could carry the costs of the mining operations, and he
targeted profit from winning the gold and silver. Chase designed the Mayflower as a state-of-the-art facility, radically improving productivity and efficiency, while also incorporating environmental innovations. Instead of dumping waste material and toxic residue into the rivers as had been historically done, Chase pioneered holding, or tailings ponds, to contain the mill’s waste material.
Because of its almost continuous use since it was built, the mill has always been kept in good repair. It was connected with the Shenandoah Mine across the Animas River canyon by a stunning, state-of-the-art, 10,000 foot aerial tram—the only tram constructed with metal towers in the San Juans. Using gravity for power, the tram carried the ore (and often commuting miners) from the mine down to the mill. Miners could then hitch a ride back up to work in an empty ore bucket.
Once at
the mill, all of the ore was dumped into one central point—where it was
crushed then ground into very fine pieces about the size of a grain of
salt. Next, through a “flotation process” consisting of various
wonderful contraptions and alchemistic potions, each grain was
separated according to its physical characteristics and routed to other
destinations in the mill. Coarse, free-gold (tempting to the
sticky-fingered) was taken away early in the process to make gold
concentrates, while other minerals went off in various directions to be
separated from the waste. From the mill, mineral concentrates were shipped to smelters for further processing and purification, while “gold sponge” (a lustrous substance, about 80% pure) was carried away by hand and shipped out of the county by U.S. mail (insured of course) most of it to be purchased by a bullion buyer, like Handy and Harmon in California. There it would finally be rendered into “9999 fine” gold bullion that would do Fort Knox proud.
In recent decades, it was ore from the Sunnyside Mine, about eight miles to the northwest of Silverton up Cement Creek, which fed the Mayflower Mill. But in 1991, the region’s gold-mining era ended when the 125-year-old Sunnyside, the last, large mine in San Juan County, ceased operations. Low base-metal prices and diminishing traces of gold and silver, coupled with new and rising costs of getting it, left the mine without profitable ore. In its colorful lifetime, over 900,000 ounces of gold were produced, millions of ounces of silver, and tons of base metals.
Sunnyside
Gold Corporation, the mine’s operator, immediately began implementing
the reclamation plan required by its mining permit, calling for the
Mayflower Mill to be torn down and the site reclaimed. But because
of the Mayflower’s historical significance to the region,
Sunnyside Gold was persuaded to donate the venerable mill to the San
Juan County Historical Society.In 2000, the Mill and the tailings ponds were designated a National Historic Landmark, one of only twenty in the State of Colorado. Grant funding has recently allowed the structure’s integrity to be assessed and documented in preparation for much-needed stabilization and repairs. The Society has applied for a “Save America’s Treasures” grant to implement the plan.
Today the Historical Society runs tours of the Mayflower Mill throughout the summer season. All of the machinery remains as it was in August, 1991, when the Sunnyside shut down, the final whistle sounded, and the Mayflower Mill closed forever. Come have a look!
Scott “Fetch“ Fetchenhier is a geologist, historian, and longtime member of the San Juan County Historical Society. He is the author of Ghosts and Gold – The Story of the Old Hundred Mine (Packrat Publishing, 1999).
Photos courtesy and copyright San Juan Historical Society. All Rights Reserved.
Top: Spiral Classifier, used to separate large and small pieces of crushed ore.
Center: Two men with bucket loaded with ore just coming into the mill. A note on the back of the photo, by the photographer, asked: “How would you like the four one-half-mile ride up in the air, to the mine, in one of these buckets?”
Bottom: Machinery inside the Mayflower Mill.