04/29/2010 GROUND PENETRATING RADAR FOR LONGER RANGE METAL DETECTION
Like earthquakes in the Pacific’s “ring of fire” tornadoes in middle America and hurricanes smashing onto America’s far east and south coasts, the technology of locating gold in the Sixteen to One Quartz beyond the current range of four feet is a question of ‘when’ not a question of ‘if’.Since 1992, this rich concentration of gold in North America’s oldest working gold mine has been a Beta site for scientists, hobbyists, goof balls and dreamers.
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.“It is great to see Andy back here with some new ideas and equipment.”
What is being developed is a portable machine that can be used in the mine to scan the tunnel walls, providing three-dimensional image showing wired gold in a transparent background.It should have a range of at least twelve feet.There are several difficulties that must be overcome in order to do this.
Obtaining adequate resolution while retaining a clear image requires solving a problem:
·The higher the frequency of the radar beam, the better the resolution, the less the range and the greater the noise from surface roughness and from internal cracks and irregularities.
This problem is being addressed by using virtual aperture and side scan technologies.A portable scanning equipment that is in development is being tested in the mine.Preliminary results show promise.