HONEY HOLE MINES LTD.
Geophysical Survey - Keithley Creek Projects
Understanding Geological & Geophysical Surveys
The essence of mining geophysical surveys is the speed and bang for the buck.
Mineral explorers rely on a wide range of geophysical techniques including magnetic, gravity, electrical, electromagnetic, and radiometric, and above all on strong knowledge of hardrock geology and on results of local field mapping and exploration drilling.
Magnetism
Magnetic exploration is much more complicated and precise than gravity. Geologists use variations in the earth's magnetic field to detect certain magnetized ores and precipitated minerals. It is good for minerals in particular, it is good for finding minerals hidden in complex rock formations. Precipitated minerals, metals that have already been smelted from the ore by heat in the earth's crust, shine particularly bright on magnetic scans.
IP / Resistivity, Resistivity, and Induced Polarization
Surveys are done by injecting a current into the ground. The electrical resistivity method uses a series of electrodes nailed into the ground about six inches deep along a selected straight profile or 3D grid. The distance between the electrodes depends on the desired depth of the investigation and the target being imaged. The further apart the electrodes, the "deeper" the electricity goes into the earth, at the expense of resolution. The most commonly used configurations activate four electrodes at a time, two for passing current into the ground and two for measuring the potential difference.
What are the Costs of Geophysics?
Cost is, of course, a key consideration. Most environmental and engineering geophysical surveys have a cost structure that is similar to that of any licensed professional: an hourly consulting fee plus equipment rental costs. In addition, there are associated costs of mobilization (since most geophysical surveys require the acquisition of data in the field), instrumentation amortization, data processing, and interpretation, and report writing and presentation.
In general, geophysical surveys are almost always substantially less expensive than traditional non-technical means of investigation such as excavation or drilling.