ORIGINAL SIXTEEN TO ONE MINE LOOKS AT GROUND PENETRATING RADAR
Domestic mine article by Harold Hough Aug/Sept 2010
With record gold prices, the Original 16 to 1 mine management sees a great future for its operations. It should know. In the last 114 years, the Original Sixteen to One Mine has seen depression, recession, high gold prices and low gold prices. It has seen California evolve from a pro-mining, wild frontier into the politically correct, mine-hostile haven it is today. Yet, despite all those changes, the mine has survived and is looking towards many more years as the country’s oldest publicly listed gold mine.
The mine began in 1896 when Tom Bradbury discovered the outcropping in his backyard was gold bearing. Ironically, it was named after the silver/gold ratio proposed by pro-silver Presidential candidate William Jennings Bryan, who was advocating policies that would hurt gold miners. Unlike most mines, it was a high-grade gold mine where there is about two to three ounces of gold per pound of quartz matrix. The gold was so rich that in the early years the gold was hand picked out of the rock, sacked, and sent directly to the San Francisco Mint. Today, some of the ore, which shows gold strings running through the quartz like a rich web, is polished and sold as jewelry.
The mine has gone through several booms and busts over the last generation. In most cases, it was innovative thinking, not rising gold prices, that helped lift the company out of the red. In the 1990s, the company had laid off its crew and was seeking investment capital to open up the flooded 2,400 foot level, when two part time miners came to them with a proposition to explore the mine in return for the bulk of the gold that they found with commercial gold detectors. Although the method was an unconventional way to explore traditional gold mines, it was ideal for the type of rich gold deposits found in this mine. As a result, the company rehired some of its crew within a month and equipped them with specially calibrated metal detectors. Thanks to this new technology, they immediately found gold and, since this method of exploration was cheaper than traditional methods, the company showed a profit in 1992.
Much of 1992 and 1993 was dedicated to renovating the mine and exploring existing tunnels with the hand held gold detectors. The detectors could find gold within 12 to 36 inches of the face and during those years the mine successfully explored 70% of the tunnels with the detectors to see what gold deposits lay just beyond the face. By using such methods, in December 1993, the mine found a gold pocket that contained 2,500 ounces. In addition to detectors, the mine also uses ground penetrating radar and radio imaging to get a better idea of what lies underground.
The good years encouraged the mine to expand and in 1995 the company began operating below the 2,400-foot level and began digging into new ground. However, the declining gold prices once again struck and the Sixteen to One had to retreat. However, many of the employees had enough faith in the company and the mine that they went to work as independent contractors, who were paid a percent of the gold recovery
LOOKING FORWARD WITH RADAR
The company has survived over one hundred years thanks to innovation - from paying workers a percentage of the discoveries to using metal detectors for prospecting underground. It was also one of the first mining companies to fully exploit the Internet to stay in contact with its shareholders.
One of the problems is finding gold beyond the few feet that metal detectors can detect. As a result, the mine is currently focusing on ground penetration radar (GPR) to find more gold. Andrew Yeiser has taken an active interest in the Original Sixteen to One Mine’s operation at the Sixteen to One for 18 years. In 1992, at Michael Miller’s request, he took his ground penetrating radar (GPR) equipment into the mine to investigate the possibility of using GPR to locate gold deposits at a distance greater than the range of metal detectors. The concept was proven by the detection of echoes from 600 feet away. Andrew has degrees in physics from MIT and UC Berkley and a deep history in practical technology.
“The mountain (Sixteen to One mine) is transparent to radar!” was the surprised remark of Lambert Dalphin, Stanford Research Institute’s GPR expert who assisted Yeiser,s introduction to the gold mine. The proof of concept was successful, yet the equipment had been designed for surface use and was not suitable for use in a mine. “Leading GPR gold detection at the Sixteen to One and other types of detection technology is natural here”, said Miller, president of Original Sixteen to One Mine, Inc. “Geologists and miners know that the mines of the Alleghany District in Northern California hold the richest concentration of gold yet discovered”, he said.
In the long run, no one knows what will happen. Unlike most gold mines, the Sixteen to One doesn’t have traditional reserves because of the nature of its deposit. However, geologists have stated the mine has only mined about 1/4 of the vein system over the past century. Given the fact that the mine has produced over a million ounces in the past 100 years, that means that there remains plenty of potential for the future.