Induced polarization (IP) research began at The Anaconda Copper Company shortly after the publication of David Bliel’s thesis and when it became known that Newmont were pursuing IP research based on the previously classified and related work by the U.S. Naval Ordinance Laboratory during World War II. The research continued at Anaconda until roughly 1980 when the focus shifted more towards hydrocarbon exploration and efforts continued at the research labs of Anaconda’s owner at the time – the Atlantic Richfield Company (ARCO).
Early in the Anaconda research, after the IP technique had been well-established as an effective tool for detecting disseminated conductive sulphide minerals, a goal was set to learn how to distinguish copper-sulfides from iron-sulfides (pyrite). Ultimately this goal seems to have been achieved, however with some uncertainty (i.e. statistically successful) and with a great number of practical challenges such as the requirement of gathering extremely good data quality (very strong signal-to-noise) at extremely low base frequencies (less than 0.01Hz). A great deal of insight into the IP phenomenon ensued and important technologies were developed such as telluric noise cancellation techniques that typically reduced noise by factors of 10 to 100. A twenty-channel system was developed and working as early as 1970 and ultimately a prototype distributed-acquisition system was built in 1986 before the long span of on-going development was discontinued shortly thereafter. Later spin-offs from the Anaconda and ARCO research were the MIMDAS and Titan-24 systems.
This report provides an overview of the understanding, algorithms and technologies developed at Anaconda and ARCO.
