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Soil-Gas Detection of Bedrock Mineralization and Geological Faults Beneath Glacial Deposits using Economic Electronic Gas Sensors

Lead Researcher(s):  D. Sacco

Project ID:  2018-028

Key Research Organization(s):  Palmer Environmental Consulting Group Inc.

Project Location:  Central Interior

Strategic Focus Area:  Minerals

Summary



This project developed an economical and portable gas measurement system to reliably and efficiently detect evidence of geological faults and sulphide mineralization buried beneath glacial sediment deposits in the central interior of British Columbia.

The Need

BC’s North Central and South Central Regions are characterized by thick glacial sediments that infill a geographic depression known as the Fraser Basin. Copper-gold occurrences that form a transect extending nearly the length of BC are noticeably absent within the Fraser Basin. New, cost-effective tools that can ‘see through’ these sediment sequences to the underlying bedrock can help support mineral exploration in central BC and beyond.

Project Goals

This project fits under Geoscience BC’s Strategic Objective of ‘Advancing Science & Innovative Geoscience Technologies’ and the goal to:

  • Increase research and development of innovative exploration and mining methods, tools, approaches and geoscience technologies.

Specifically, this project:

  • Tested portable and cost-effective soil gas survey technology in the field over two areas where structures and mineralization are buried beneath a thick layer of glacial sediments.

Project Benefits

Soil gas sampling has the potential to help identify new natural resource opportunities in an area of BC that may host undiscovered mineral deposits. The results of the project will bring an innovative and proven mineral exploration method to BC in the form of a portable, cost-effective device.

Survey Area

The method was tested at two field locations:

  • Mouse Mountain 13 km northeast of Quesnel. The location for the Mouse Mountain MINFILE (# 093 003) is 14 km northeast of Quesnel. The primary MINFILE name from the BCGS data is Mouse Mountain, it has a secondary MINFILE name of Wanda.Shiko 14 km north of Horsefly. The location for the Shiko MINFILE (# 093A 058) is 15 km north of Horsefly. The primary MINFILE name from the BCGS data is Redgold, it has the secondary MINFILE name of Shiko.

These locations were chosen based on the inferred occurrence of faults, the existence of copper-gold porphyry-style disseminated sulphide mineralization and a cover of glacial drift.

What Was found?

Soil gas and soil were sampled along transects crossing faults associated with mineralization to compare the soil geochemistry with the soil gas carbon dioxide and oxygen concentrations. The soil gas over the inferred faults is enriched with carbon dioxide and depleted in oxygen as compared to the soil gas over surrounding rocks. Results of the soil chemistry indicate the soil gases likely reflect oxidizing sulphides within the bedrock.

The researchers found that the system reliably measured carbon dioxide and oxygen variations in soil gas in real time, that the equipment is field-portable, and the process is efficient. Additional testing of the system is still needed to help determine if the procedure and system can detect different styles of buried mineralization and varying overburden thicknesses.

Deliverables