This project evaluates the effectiveness of using portable photometers and voltammeters which measure light as it passes through a water sample -- to provide quality, same-day water analyses for mineral exploration.
Analysing water samples has traditionally been time consuming and expensive. It was proposed that Geoscience BC investigate whether in-the-field water analysis technology is a viable mineral exploration tool as part of the larger TREK project. Having proved successful, the technology could potentially be used to provide a faster and more economical information about minerals. Nazko Economic Development Corporation contributed in-kind and logistical support to the project because it was interested in assessing the potential for resource-based economic development in the study area.
The project was designed to:
This project tested a new methodology to quickly detect indicators of mineralization using water samples at low cost. The data provides new information regarding minerals from water analyses that can be used by governments, First Nations and industry to make more informed resource decisions in the Nazko River Valley.
Using portable photometer and voltammeter instrumentation, the survey provided a regional dataset to supplement existing stream and lake sediment surveys, and geochemical surveys, in the Marmot Lake area. It also provided guidance as to the most effective time of year to conduct water analysis, considering factors such as precipitation levels and water turbidity (when water becomes cloudy or ‘muddy’ from an abundance of solid particles).
The project area was located south of the town of Nazko, about 75 kilometres west of Quesnel. The study was within the traditional territory of the Nazko First Nation, which has 19 reserves. The area has an abundance of water bodies including creeks, lakes, wetlands and bogs. Two fast-flowing rivers run through the project area — the Nazko and the Baezaeko. There are two sulphide mineral occurrences within the project boundary.
Researchers collected about 100 water samples from lakes and streams in the Nazko River Valley, from May to October 2016. The samples were then analyzed in the field and compared with laboratory analysis of the same samples. The analyses were carried out within 24 hours of collection using both photometers and voltammeters (PDV), and retested for quality control. Sample locations were tested for temperature, pH, conductivity, total dissolved solids and salinity. Identical procedures were used for samples sent to the ALS Environmental laboratory in Burnaby, BC, except for filtering on site for dissolved-metals analysis. Testing was limited to copper, lead, arsenic and cadmium.
The project demonstrated that a portable photometer can be an effective means of obtaining rapid and low-cost detection of elements in surface waters, allowing more samples to be collected in a project area. The final report discusses methodology outcomes, such as the need for orientation surveys, the finding that sample filtration is unnecessary and observations on analytical reliability and on seasonable variation. Final results show that the portable photometer was able to detect elevated copper and arsenic concentrations in water near known mineral showings. Two drainages with no known sulphide mineralization but elevated copper and sulphate have potential for follow-up.