Hardrock Mining Today
Notes from a presentation at the October 20, 1999, meeting
of the Gold Prospectors of the Rockies

As appearing in The Gold Nugget, November 1999
by Steve Rice, Colorado Nuggets

[Hardrock mining.]

The mining experience that Steve Rice has spans more than 25 years at the Henderson Molybdenum Mine at the base of Berthoud Pass. His workday is twelve hours long with a half-hour paid lunch period. Within the mine, diesel powered tractors move miners from the work area to restrooms and such. Temperature in the mine ranges from 50 degrees to 100 degrees Fahrenheit. When water is found, it can range from very cold, through lukewarm, to upwards of 120 degrees.

The entrance to the Henderson is at 10,500 feet elevation. The mine is 3,500 feet deep with five shafts. Interestingly, because of the rock, miners cannot communicate by radio. The mine's elevators can take 200 miners down at one time. The trip takes ten minutes.

The Henderson crew is one of the finest anywhere in the world. Each month, the rescue team goes through safety and rescue training.

Steve showed many slides of the types of equipment used in the mine, from ring and jumbo drills to hole bolters to muckers to a thirty-mile-long new-technology conveyor belt that goes over a trestle that the rescue team uses for rappelling.

The mine has produced over 575 million pounds of ore, yielding 4.82 pounds of molybdenum per ton, which is floated and shipped to a roaster back east. Tungsten and lead are found, but not enough to be profitable to extract. No gold is processed. The rock at the Henderson gives up its molybdenum much more readily than is found at other areas.

It is estimated that the mine can be profitable at least until 2020 before it will have to close down. When that happens, the Climax mine, which had armed guards stationed around it during World War II, will probably be opened.

Barometric pressure varies greatly in the mine, sometimes bringing in air, but also sometimes sucking it out and oxygen must be pumped into the mine. Carbon dioxide will displace oxygen from rocks and accumulate in the mine. Because CO2 is odorless and colorless, by the time you realize you are in trouble from oxygen deprivation, it can be too late for survival.

The Henderson is very conscious of environmental concerns. The mine disposes of quantities of mercury which were not put there by the mining processes.

Transcribed by Dick Oakes

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© 1999 Gold Prospectors of the Rockies