BC’s northern Interior Plateau region is host to several mineral deposits, including the proposed Blackwater gold-silver mine, and has the potential to host many more. The bedrock geology of this underexplored region is largely buried under a blanket of glacial sediments of variable thickness, masking the characteristics of the rocks below. However, certain materials found at the surface can be sampled and analyzed to find trace amounts of the valuable elements, such as gold, copper or molybdenum, below. Sampling these surface materials is easier and less expensive than some other exploration methods, such as drilling, and generates valuable information for explorers focus their search for new mineral resources.
This study extracted and analyzed the clay-sized fraction of over 1,000 samples of till — the mix of gravel, sand and clay left behind after glaciation has affected an area — to produce a more precise, regional-scale data layer for explorers and land managers to use in making decisions about exploration activities and land use in the area. It also evaluated the cost-benefit of the additional cost required to separate the clay-sized fraction for geochemical analysis.
The TREK till analysis project was designed to:
- Collect all available till geochemical analyses in the TREK area
- Interpret using exploratory data analysis (EDA) and other geochemical analysis techniques
- Generate and deliver geochemical data layers to help delineate areas of increased mineral potential.
Earth science information gathered from easy-to-access sampling materials helps attract mineral exploration investment to the province, creating jobs and building diverse, sustainable communities. Re-analyzing a portion of previously-collected samples adds value to public geoscience datasets by eliminating the cost of sample collection. Better interpretation of anomalies in existing data increases the likelihood of discovering buried mineralization. In addition to identifying mineral opportunities, the availability of new regional earth science data provides First Nations, regional districts, governments and communities with a better understanding of the resources in their area leading to more informed land-use and resource management decisions.
The TREK project covers a 28,000 km2 area in BC’s Central Interior Plateau from Anahim Lake in the southwest, north and east towards Burns Lake, Vanderhoof and Williams Lake. New Gold’s proposed 8.2 million-ounce Blackwater gold mine is located in the middle of the area, about 160 kilometres southwest of Prince George. See TREK project page for more information.
How was the Data Collected?
Between 1994 and 2015, over 3,000 till samples were collected by various field teams from the British Columbia Geological Survey (BCGS), Geological Survey of Canada (GSC) and Geoscience BC. Samples from the BCGS and GSC campaigns were reanalyzed as part of the TREK project (LINK) to ensure consistent data quality.
This project used exploratory data analysis (EDA) — a well-documented method used in mineral exploration for over 50 years — to identify trends in the data. EDA was performed on 2,709 till samples selected from the full dataset. This analysis highlighted trends in the concentrations of elements, including the porphyry pathfinder and immobile elements, such as gold, copper, and arsenic, that suggest the presence of a copper and/or gold mineralization. The method validated the data against existing mineral deposits in the region and highlighted new areas to look for buried mineralization.
What was Found?
Plotting the results of the EDA identified know mineral occurrences in the area, including the Blackwater deposit, the Pollyanna deposit (part of the Gibraltar mine) and Chu deposit near Vanderhoof. In addition, several new targets were generated in areas without known mineralization.