Every mineral deposit is unique and requires a large number of items to consider when conducting a Mineral Resource Estimate (MRE) with some items more important than others. While Micon’s Competent/Qualified Persons may approach and conduct an MRE from a variety of perspectives the following top 10 tips generally summarize Micon’s approach to conducting an MRE.
- Data is the foundation of everything in MRE. Remember: garbage in = garbage out!
Take a critical look at the source information, units, datum, logging and sampling procedures, assaying methods, and Quality Assurance and Quality Control (QA/QC) protocols and the results from standards, blanks and duplicates.
- Do a thorough statistical analysis of the raw assays, make categories of the data sources, sample types, assay methods, and compare. Then do the same within the Geological Domains using raw assays and composites.
- Understand the geology of the mineral deposit first, and the rest will follow.
- Ensure that the Geological Domains are constructed for estimation purposes (search strategy), must always honour the data, connect the dots, and don’t invent information: simplicity is the ultimate sophistication.
- Composites are the crux of the entire mineral resource estimation (MRE) process; they must be appropriately sized, declustered, coded, and capped.
- Geo-Statistics. Geology must always be the first consideration followed by the variograms. Geostatistics provides useful tools to decide the estimation parameters, and to confirm the geological interpretation, but, Geostatistics is not the panacea of MRE.
- Block size should not be too small nor too big. It needs to represent the available data spatially (3D), but estimation error is inversely related to block size. Think ahead, and speak to the mining engineers: block size must support the proposed mining method.
- Density data is essential, preferably bulk density. Make sure you have enough data for each rock type throughout the mineral deposit (waste and mineralization).
- All resource models are wrong to some extent, but some are useful. Double-check everything, validate results, correct and repeat, do some fine tuning as required, keep in mind that MRE is an Art combined with Science, it is not an exact calculation. It is an estimation.
- Follow the public reporting code in your jurisdiction; a “Mineral Resource” can be called a Mineral Resource only when it has reasonable prospects for economic extraction, and it must be constrained within the boundaries of a suitable mining method.
Each of the top ten tips will be explained in more detail in an upcoming series of articles called ‘Journey to a Mineral Resource Estimate’.