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Comet Resources reveals bonanza-grade gold in re-assays of historical core at Santa Teresa Gold Project

Published: 21:48 31 Aug 2021 EDT

Comet Resources Ltd - Comet Resources unearths bonanza gold grade ins historical drill core re-assay at Santa Teresa Gold Project

Comet Resources Ltd (ASX:CRL) has unsurfaced up to 132 g/t gold during a resampling program on historical drill core from the Santa Teresa Gold Project in Baja California, Mexico.

The gold explorer evaluated core from 22 holes drilled during a 2008 exploration campaign, discovering bonanza-grade gold hits that could bode well for a diamond drilling program that got underway in June 2021.

Comet also retrieved rock chip and soil samples from the project’s quartz vein outcrops and waste dump material near historical workings, uncovering as much as 9.5 g/t gold.

Meanwhile, a metallurgical test-work program indicates that most of Santa Teresa’s gold is ‘free milling’, meaning high levels of the precious metal can be recovered without pressure leaching or other chemical treatment.

Assays correlate with metallurgical tests

Comet Resources 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, whereby with 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.”

Time travel to 2008

Before the 2021 drill campaign got underway, Comet’s Mexico-based geological team completed a detailed review on Santa Teresa’s historical drill cores.

A suite of drill holes from 2008 underwent re-assay in a bid to better define the project’s geochemistry and the link between veins that were previously intercepted and those that outcrop at the surface.

Notably, Comet’s program unearthed several high-grade gold intersections and even some bonanza-grade hits within the historical diamond drill core.

Some of the best results include:

  • 1-metre at 132 g/t gold from 112.7 metres;
  • 1-metre at 52.8 g/t from 20 metres;
  • 1-metre at 27.9 g/t from 142 metres; and
  • 1-metre at 24.9 g/t from 217 metres.

In tandem with the historical re-assaying, Comet collected 37 surface samples at Santa Teresa for further review.

Like the 2008 drill core, samples made their way to ALS’ Vancouver laboratory for analysis and returned anomalous gold up to 9.5 g/t gold.

Key findings

Ultimately, the re-assay and fieldwork suggest two gold systems exist within Santa Teresa, the older of which appears to be a typical mesothermal, lode-type system.

On the other hand, the other system appears to be a low sulphidation epithermal system related to more recent intrusive events.

Coarse gold mineralisation was found in many of the re-assay and surface samples, such that the “nugget effect” is likely to be a source of discrepancy between the 2008 and 2021 programs.

In order to examine this more closely, ALS Chemex was asked to use leftover samples with higher contrasts in gold results for further analysis.

Positively, this particular assaying method considerably decreases the nugget effect and smooths out the discrepancies in gold values.

Looking ahead, Comet believes its latest review will underpin future drill planning and metallurgical test work at the Baja California gold play.

Metallurgical test-work results

In addition to the re-assay and sampling program, the ASX-lister undertook phase one of its metallurgical test-work program over a 25-kilogram sample from Santa Teresa’s historical sample pulps.

The average head assay returned around 11 g/t of the yellow metal, with results indicating coarser gold is present in the sample.

ALS reported there is clearly gravity recoverable gold in the sample, with between 46% and 60% of the gold recovered across a range of grind sizes.

Additionally, 83% to 90% of the gold in the gravity tailings was recovered in rough flotation concentrate.

All in all, the combined gold recovery from gravity and floatation ranged from 91% to 96%.

The high recoveries confirm Comet’s view that Santa Teresa Gold Project’s gold is ‘free milling’ and amenable to low capital and operating cost gravity and flotation processing solutions, should a decision to mine be made in the future.

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