Using cutting-edge technology to build on good fieldwork at Avispa
October 3, 2022Montero Mining is using innovative technology to assess the potential of porphyry copper mineralisation at its Avispa project in northern Chile, following thorough mapping and sampling at the project. The company’s CEO and President Dr Tony Harwood sheds more light on the positive 3D modelling results.
Q: Three-dimensional modelling at Montero’s Avispa property, conducted by Fathom Geophysics, shows a significant porphyry copper target under an area in the southern part of the property that has seen limited drilling in the past. This sounds like a promising and exciting result?
A: It is extremely exciting. A clear and coherent porphyry target has been identified through geochemical analysis of reverse circulation drill-chip piles on the surface and Fathom’s modelling of the data. Fathom analysed this dataset with its proprietary software by comparing it to idealised models of mineralised porphyries that have been studied and researched extensively. The depth of the identified target is unknown because the drilling depth of the samples collected from the surface is unknown but the location is well defined by the modelling.
Q: Is the technology and method that Fathom used to assess the geochemical data new?
A: The short answer is yes. Many years of research on porphyry copper systems has shown that signature elements and their ratios can indicate proximity to a porphyry copper mineralising system. Modern techniques of sample preparation and chemical analysis can detect minute levels of these indicator elements, and this has proved extremely useful for vectoring into blind porphyry copper systems below the surface of the ground.
All samples are prepared by four-acid digestion followed by chemical analysis using a sophisticated mass spectrometer. Fathom has developed an algorithm that models the spatial distribution of trace elements in an exploration project dataset and compares the results with an ‘idealised’ chemical footprint of a porphyry copper system. These systems are now becoming well-known through discovery and research. The strength of similarity between the project data and the ‘idealised’ porphyry copper model is used to generate 3D volumes representing the x-y-z probability location of porphyry copper mineralisation.
Q: Fathom’s analysis has been successful in identifying existing porphyry copper mineralisation at depth in other South American locations like Ecuador. How tried and tested is this new software?
A: This information is proprietary to Fathom, but we know that a small and growing number of exploration and development companies are publishing Fathom work and data. Many larger companies that are using or looking at using Fathom’s technology would not publish this information and keep their data confidential. Exploration is a highly competitive business and innovative technology like this is often a closely guarded secret.
Q: Does the generation of the 3D target at Avispa open the way for drilling or more advanced exploration?
A: Most definitely yes, but we need to do more work on defining the target. In fact, this is what we are concentrating on at the moment.
Q: Montero is evaluating other areas on the property to generate more mineral targets. Would the porphyry target that has just been identified by Fathom be sufficient for the group to prove an economic deposit at Avispa?
A: In exploration it is often tempting to drill the first target that is developed, but this is not the best course of action. I am sure our work will result in the development of further targets that will be ranked along with other exploration criteria. For example, other methods to better define drilling targets at our disposal are modern geophysical techniques.
Q: Is Montero planning to use other frontrunning technologies in its drive to discover a significant porphyry copper-molybdenum deposit at Avispa?
A: Greenfield exploration is difficult even if you are in the right location, and we have 500 km2 of concessions to explore. At Avispa, surface geology indicated that any potential porphyry copper deposit would be located under tens of metres of Atacama Desert sand and Miocene sediment and gravel. State-of-the-art remote-sensing and analytical AI techniques are scientific methods which help us target a discovery area, but inevitably discoveries can only be made by drilling. Serendipity is also important, and although there is a long road ahead, the first few steps have been secured and the property is 100% held by Montero.
Q: How do you feel about the overall progress of your exploration programme at Avispa?
A: I am very pleased with our progress. The positive outcomes are a result of good geological mapping and sampling driven by our boots-on-the-ground approach. We are building on this by using innovative technologies to make a discovery.
Images showing the interpreted geochemical zonation around idealized porphyry copper systems used by Cohen (2011, left) and Halley (2015, right).