Resource & Reserve
In April 2019 the Joint Ore Reserve Committee (JORC) adopted the “Guidelines for the Resource and Reserve Estimation for Brines” (Guidelines) that have been jointly developed by the Australian SOP Brine Industry and its specialist hydrogeologists in conjunction with the Association of Mining and Exploration Companies (AMEC).
The Guidelines were developed to assist the industry to describe the technical considerations required to report brine mineralisation, Resources and Reserves in relation to the JORC Code 2012 which, unlike solid minerals, requires an understanding, and definition, of the aquifer characteristics (hydrogeology) plus the host geology.
Importantly, under the Guidelines:
- Companies and competent person(s) will report Exploration Results and Mineral Resources Estimates based on Specific Yield (Drainable Porosity) and not Total Porosity. This is important as Total Porosity may be substantially larger than the Specific Yield and includes brine that cannot be abstracted. Consequently, the incorrect or inappropriate use of Total Porosity may result in a material over-estimate of the potential amount of brine that can be economically recovered.
- Reporting of brine based Ore Reserves should further consider the Modifying Factors and temporal components specific to brines (as outlined in the Guidelines).
Kalium Lakes confirms that its Beyondie Sulphate of Potash Project Ore Reserves and Mineral Resources is compliant with JORC’s newly adopted Guidelines for the Resource and Reserve Estimation.
Kalium Lakes has adopted both the JORC Code and the Canadian Institute of Mining, Metallurgy and Petroleum (CIM) NI 43-101 standard of disclosure for the reporting of Mineral Resources and Reserves.
The CIM has developed best practice guidelines for mineral resource and reserve estimation of Brines which requires the following to be determined:
- The extent of the Brine body and aquifer geometry;
- Brine elemental chemistry and variability;
- Total porosity (Pt) and effective (drainable) porosity (Pe);
- Specific yield (Sy) = yield of drainable fluid obtained under gravity flow conditions Pe = Sy + Sr (where specific retention (Sr) = retained fluid in aquifer material);
- Permeability, hydraulic conductivity and transmissivity of sediment lithology;
- Only specific yield should be used as the measure of total brine endowment not total porosity. This requires pump tests of sufficient duration to determine parameters;
- Ore Reserves need to consider bore field engineering, evaporation parameters and suitable process flowsheets for cost effective recovery of the target metal ions; and
- Brine resources and Brine reserves are to be reported as available cubic meters of Brine with a grade for the valuable elements (e.g., K and Mg).