A Test of Deep Penetrating Geochemical Techniques on Covered and Blind Porphyry Deposits in the QUEST Project Area (NTS 93N)
- Dave Heberlein, Heberlein Geoconsulting

Project Study Porphyry Deposits Location Exploration geochemistry in British Columbia has up to now relied on traditional methods such as stream sediment and soil geochemistry to detect metals dispersed mechanically and hydromorphically from out cropping sources. These methods have proven to be highly effective and there has been a long and impressive history of discoveries using them. As exploration maturity increases however, mining companies are faced with the challenge of exploring more and more in areas of transported cover where traditional methods are less effective or don't work at all. Much of the Central Interior of British Columbia is covered with a veneer of glacially derived sediments that completely mask the underlying bedrock. As a result, exploration companies have switched their focus from geochemical methods to a more geophysical approach that seeks to define favourable geology beneath the glacial cover using airborne magnetic, gravity, electromagnetic and radiometric techniques. Unfortunately these methods only provide indirect knowledge of the bedrock geology and ground geophysics is often necessary to validate the airborne geophysical results and define drill targets.

What is missing from the explorationist's toolkit is a geochemical method that can be used to follow up the airborne and ground geophysical targets that can provide a direct measurement of the trace element characteristics of a blind target. Such a method would prove invaluable for prioritizing drill holes and could significantly reduce the number of 'dry' holes drilled into geophysical targets thereby reducing a company's drilling risk.

Partial leach geochemistry has the potential to become an important part of future exploration programs in the covered areas of BC. Unfortunately little work has been done to optimize methods for typical BC environments and little of what has been done has not reached the public domain.

This project presents a case for carrying out two orientation surveys to test a range of commercially available partial leach methods on blind porphyry copper targets with the objective of optimizing sampling and analytical methods for two contrasting environments (i.e. logged vs unlogged, glacial outwash vs. till cover). Two orientation sites proposed are: The Central Zone at Serengeti's Kwanika project and the MBX and 66 Zone at Terrane Metal's Mt Milligan project.

Kwanika Location Map
(click on image for larger view)

Mt Milligan Location Map
(click on image for larger view)
Technical Articles
2010: "Comparative study of partial and selective extractions of soils over blind porphyry copper-gold mineralization at Kwanika and Mount Milligan, central British Columbia (NTS 093N/01, /19): fieldwork, soil conductivity and pH results"
- Summary of Activities 2009, Report 2010-1 p.11-24 (pdf, 8.8 MB)
Final Deliverables
Geoscience BC Report 2010-3
An Assessment of Soil Geochemical Methods for Detecting Copper-Gold Porphyry Mineralization through Quaternary Glaciofluvial Sediments at the Kwanika Central Zone, North-Central British Columbia

As part of a Geoscience BC funded study, a geochemical orientation survey was carried out over the blind Central Zone Cu-Au porphyry deposit at Serengeti's Kwanika project in north-central BC. The objective of this study was to test various widely used partial and selective extractions in a challenging cover environment to determine which performs the best at detecting the mineralization. In addition, the study aims to provide the mining industry with guidance on the optimum combination of soil horizon and extraction method for detecting deeply buried mineralization in areas of thick glacial cover.

Results of this study show that in order to be successful, a soil sampling program over Quaternary glacial sediments in north-central British Columbia should should collect the Ah horizon samples and use an aqua regia-low detection limit ICP-MS analyses. In addition field based soil pH and conductivity measurements should be utilized in order to identify potential reduced chimneys over blind sulphide mineralization.

Geoscience BC Report 2010-08
An Assessment of Soil Geochemical Methods for Detecting Copper-Gold Porphyry Mineralization through Quaternary Glaciofluvial Sediments at the WBX-MBX and 66 Zones, Mt. Milligan, North-Central British Columbia

This report is the second and final part of a Geoscience BC funded project (Project 2009-019) carried out by the author to test the effectiveness of a variety of commonly used chemical extractions at detecting mineralization through thick Quaternary glaciofluvial cover. The first part of the study was carried out at the Kwanika Central Zone and released as Geoscience BC Report 2010-03. This final report focuses on Terrane Metals Corp.'s Mt. Milligan Copper-Gold Project.


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