Old data confirms bonanza gold in Comet Mexican project

Australian junior explorer ASX listed Comet Resources has confirmed recent re-assaying of diamond core from the 2008 drilling program at their Santa Teresa project has proven intersections of high-grade gold, including ‘bonanza’ grade hits of up to 132 grams per tonne gold.

The company has completed several work programs at its Santa Teresa Gold project in Baja California, Mexico including re-assaying of historical drill-holes from a 2008 diamond drilling program, analysing samples from a surface sampling program and phase 1 metallurgical test work.

Significant drill core intersections include 1 metre at eye-watering 132g/t gold from 112.7m, 1m at a spectacular 52.8g/t gold from 20m and 1m at whopping 27.9g/t gold from 142m.

In addition, 37 samples were taken at surface from dump material, rock chips and surface outcrop of previously unmapped veins which have returned gold results of up to a more than respectable 9.5g/t.

Comet’s Santa Teresa gold project in northern Mexico, immediately south of the town of El Alamo, comprises four granted mineral claims that cover more than 500 hectares with the centrepiece of the project being the high-grade Santa Teresa gold deposit. Gold production in the El Alamo district dates back to the late 19th century with the region producing gold from a network of alluvial and artisanal workings, in addition to the underground mine at Santa Teresa.

The area has been worked patchily since that time before Comet acquired the Santa Teresa project late last year and rapidly shifted exploration into high gear. The company’s assessment of the deposit produced a JORC resource estimate, based on the historical dataset, that weighed in at a healthy 369,000 tonnes grading at an impressive 7.47 g/t gold.

The assays on historic diamond drill core were performed on 95 samples that were selected after reviewing a massive 7,025m from a total of 32 drill-holes from the 2008 drilling program at Santa Teresa. Comet’s aim was to correlate significant intersections previously sampled using more modern quality control protocols.

The 37 samples which were gathered from surface sampling and quartz outcrops have since been prepared and sent to the lab Vancouver for assaying.

Comet geologists have analysed all the assay data and suggested a new geological model for the deposit based on this combined geochemical data. They suggest that two separate gold mineralisation systems have affected the area, the older of which appears to be a typical meso-thermal “orogenic” lode type system characterised by the correlation of gold to tellurium and arsenic, however with an absence of silver and base metals.  Intriguingly, they suggest later low-sulphidation epithermal system has overprinted the earlier event, due to high silver, zinc and lead values as well as the presence of elevated bismuth associated with the gold in certain assays. This overprinting of the original gold system has substantially upgraded the gold numbers.

The re-sampling and assaying program also identified coarse gold mineralisation in many samples but not in others implying that the “nugget effect” is likely the source of discrepancy between the 2008 assay program and the 2021 re-assay program. To examine this more closely, Comet utilised a method that considerably decreases the nugget effect and as a result managed to smooth out discrepancies that were evident in the previous gold values.

Comet has also released their Phase 1 metallurgical test work results that show an average head assay of approximately 11g/t gold. Importantly from a cost perspective, the initial test work indicates most of the gold is ‘free milling’, producing recoveries of over 90 per cent with a simple gravity and flotation circuit.  

Comet Managing Director, Matthew O’Kane, said: “The re-assay of the historical drill core confirms the prior assay results, with intersections of very high-grade material. It also confirms the coarse gold/nugget effect apparent in the deposit, with variances being observed between some of the prior assay results and the current assay results, both higher and lower. The coarse gold seen in the assay results correlates well with the excellent metallurgical test results, where with the use of only gravity and floatation, we were able to achieve very high recoveries in excess of 90%. This is positive news as it is likely that a low-cost, free milling processing solution can be employed if a decision to mine is made.”

Comet now appears to have its eye on the prize at Santa Teresa and local explorers will be waiting to see what they knock up in their recently acquired copper-gold ground in Australia’s Northern Territory.

Is your ASX-listed company doing something interesting? Contact: matt.birney@businessnews.com.au