LETTERS TO THE EDITOR — Escondida discovery in Chile

Recent letters by Siegfried Muessig and Patrick Burns published in The Northern Miner have challenged my role in the discovery of the Escondida orebody in Chile. Theirs are remarkable assertions, given the documented history of the project.

I conceived the idea of a fast-moving, regional, porphyry-copper exploration program in the Atacama Desert of northern Chile in 1978. Utah International agreed to sponsor the program and its exploration manager, Robert Wheaton, approached Getty Minerals to help spread the financial risk. Exploration managers of the two companies made up the “management committee.” The program was run by a “technical committee” which met every quarter, and to which I made recommendations that were in every case accepted. I opened an office in Antofagasta and hired personnel, including chief field geologist Francisco Ortiz. I purchased the equipment and hired the contractors. For more than two years I spent most of my time in Chile and visited every exploration prospect and every significant outcrop. When I was not in Chile, I was in constant communication with Ortiz. In short, I planned the program and supervised the work. In the case of Escondida, no Utah or Getty staff member had been on the ground before the discovery.

Burns was hired to supervise the drilling contractor. He had no role in the geologic planning and no voice in the drilling decisions. Harold Courtwright never visited Escondida but had written a report a year earlier incorrectly concluding (on the basis of outcrop specimens) that strong, near-surface, supergene leaching represented hydrothermal leaching.

Courtwright believed the capping represented high-level mineralization, possibly indicating primary copper at a depth of “say plus or minus 1,000 metres” and he speculated that any chalcocite blanket was of “limited thickness and extent.” He recommended drilling pinpoint targets where we had found the strongest geochemical values in the outcrop.

I felt the leaching represented widespread chalcocite enrichment and selected a wide-spaced, grid drilling pattern to test this theory. I located some of these holes on the geochemical highs, as would any exploration geologist. The Atacama project was specifically aimed at the discovery of a large, high-grade chalcocite blanket and we had no interest in a primary target at a depth of 1,000 metres. The drill rig I sent to Escondida had a maximum depth capacity of only 450 metres and could not have tested Harold’s targets. Any competent geologist who might read Harold’s report and compare the selected drill sites would conclude we were not on the same track. I don’t mean this as a criticism of Harold, because I think he was among the foremost exploration geologists of his generation, but he did not have an opportunity to visit the site.

It is unfortunate there was an immediate effort (which obviously continues) to distance me from the discovery, but there is ample documentation of my role. I have my contract with Utah and Getty, and Courtwright’s report. Wheaton published a paper which describes the discovery, and Minera Escondida distributed a brochure describing the history of the project. Ortiz is available for confirmation. Finally, there is no disputing that I was paid a substantial finder’s fee for the discovery.

Certainly, Escondida was a team effort and several people from Utah and Getty deserve credit for their constructive efforts on the management side. Ortiz and Donaldo and Nivaldo Rojas were indispensable in the field work. No amount of barking, jostling … will enhance the roles of others, however. J. David Lowell

Rio Rico, Ariz.