Beginning with the End in Mind

Exploration practices to maximize resources and minimize discovery costs.

Resourceful Geoscience Solutions is a boutique mineral exploration consultancy delivering high value technical services to the mining and exploration industries. We drive strategic exploration through a commitment to geoscientific first principles. One of our operating principles is to Begin With The End In Mind. That means we plan to succeed. We plan and perform all our services believing that work may eventually contribute to a mineral resource estimate (MRE). We believe that planning to succeed leads to more efficient discovery and a greater resource return for our client’s exploration expenditures.

The following discussion highlights the most common ways we see mineral exploration projects look to save time or money which can actually create costly corrections at the time of a MRE or prevent your hard work from contributing its full value to a MRE. Regardless of the size scale or scope of your mineral exploration program there are a few straightforward, low-cost practices that can be implemented to ensure all your exploration efforts and data can contribute their maximum benefit to a MRE. You may be at a stage in your project where resource estimation is many years down the road, but it will always be more cost effective to collect data in a resource ready way from the beginning.

Quality Assurance and Quality Control

A robust and well documented quality assurance/quality control (qa/qc) program aligned with the most up to date Canadian Institute of Mining (CIM) best practice guidelines is a necessary consideration for the collection of all geoscience data but analytical data most especially. If your assay data is not qualified by an industry standard and well documented qa/qc program, it’s inclusion in a MRE may require extensive data verification efforts or may not even be possible. This may cost significant money and time. The specifics of your qa/qc program will be catered to the nature of your deposit and the scope of your work. However, all quality control programs typically involve the inclusion of banks, certified reference material, and duplicate samples in a frequency that provides statistical confidence.

The other side of side of the qa/qc coin is data security. For your data to remain valid over time it is best to be maintained and controlled in a demonstrably secure manner. We suggest a relational database with written change management procedures and an audit log.

Drill Core and Channel Sampling Protocol

Improper or ineffective drill core sampling might save you on your laboratory bill but may serve to depress the true grade or tonnage of your deposit’s MRE. Common issues arise from inappropriate sample widths and inadequate shoulder sampling or sample continuity. Estimation domains are more robustly modelled if the mineralization of interest is sampled continuously through the mineralized zone and closed by unmineralized or uneconomic shoulder samples. Inadequate shoulders can potentially create a loss of resource volume. Selective sampling through the mineralized zone can leave drill hole intervals unsampled within the estimation domain. These intervals, if not resampled, are typically substituted with zero values potentially reducing the average grades and lowering the total mineral inventory. Generally, continuous sampling at widths that respect the width and continuity of your mineralization will produce the most favorable results.

These same considerations apply to channel sampling. If collected thoughtfully channel samples may contribute the same value to a MRE as drillholes. Channel samples can be a lot of work to collect and often these are treated as just outcrop grab samples but with a small amount of additional effort this data will add a new level of value to your exploration program. The best way to get the most from your channel samples is to simply treat them as horizontal drillholes, applying your same drillhole logging, surveying and sampling practices.

Petrophysical Characterizations

Petrophysical characterization means measuring the physical properties of your geology. At the highest-level geophysical surveys measure contrasts in various physical properties through the bedrock. Be that magnetic susceptibility, electrical chargeability, electromagnetic conductivity, or density etc. Petrophysically characterizing your projects geology in the field, and/or the core shack allows for the most robust interpretation of existing geophysical surveys and most effective planning of new exploration geophysics.

Specific to mineral resources, material density or specific gravity (SG) is a necessary variable in mineral resource estimates needed to calculate the mass and therefore mineral inventory of your deposit. To achieve the most accurate calculation it is not only important to measure the SG of each lithological unit within the deposit but the different altered and mineralized phases of those lithologies that may also be present. Your SG dataset should include representative samples of all lithologies both altered and unaltered as well as mineralized and unmineralized in statistically valid populations. A good rule of thumb is that any lithology, alteration, or mineralization phase that can be modelled should have a statistically valid population of SG measurements.

Drill hole Spacing

A common source of disappointment in the results of a mineral resource estimate is when great drill hole intercepts do not translate into a large mineral inventory. Commonly, this is the result of ineffective drill hole spacing. Drill holes may be spaced too far apart, and intercepts cannot be confidently correlated between holes. Conversely, holes that are spaced too closely may provide continuity but fundamentally share the same volume. The most effective way to increase the inventory of your mineral resource estimate is not only drilling for high grades but also for large volumes, it’s a two part equation; grade and tonnes. An ideal spacing is specific to the geological conditions of your deposit and strategic direction of your exploration program. What is most important is that optimizing your drill hole spacing is a consideration in your exploration planning.

Drill hole surveying

When I discuss drill hole spacing a more appropriate term is intercept spacing, and it is not possible to optimize your intercept spacing without accurate downhole surveys. While leaving drill holes open and surveying after the completion of your program is an option in some cases, we would discourage it. Adapting your drill plan to unanticipated drill hole deviation on the fly will ensure that you can realize the optimized hole spacing you intended and the best value from your drill dollars. A simple survey of dip and azimuth at the drillhole collar which does not consider downhole deviation is not sufficient.

Geological mapping and modelling

A confident understanding the geological setting and mineralizing processes is invaluable to not only the confidence of your mineral resource estimate but the overall success of your exploration efforts. The most effective way to build this confidence and understanding is through ongoing and iterative 3D geological modelling and geological mapping throughout the exploration of your deposit. This practice will maximize the effectiveness of every exploration dollar by reducing unnecessary drilling. The best geological maps and models consider structure, lithology, alteration, and mineralization.

In Conclusion

There are countless considerations that go into the development of an exploration plan and certainly more than one right way to do it. The practices outlined in this article are just some of the small efforts you can make to ensure that you realize the greatest resource return for your exploration expenditures and get the maximum benefit from every program. Resourceful Geoscience Solutions stands ready to assist our clients throughout their exploration journey providing a full suite of mineral exploration services from the desktop to the outcrop.

David Murray P.Geo

President and Principal Consultant

Resourceful Geoscience Solutions