Reach Resources’ remodelling of its “Murchison South” gold project as part of a strategic review has identified a number of open mineralised zones at its Blue Heaven prospect.
The review of the project, located near Payne’s Find in Western Australia, has led to a theoretical repositioning of the Primrose Fault - a key mineralisation control at the project – which has exposed gaps in the block model and opened-up Blue Heaven’s western flank for further exploration.
Reach says the data gaps in the model will be addressed as a priority with infill drilling to confirm immediate open-pit resource opportunities. Additionally, the project’s re-evaluation has identified other immediate drilling targets with significant potential across the greater project area.
The work was prompted by the company’s desire for a strategic audit of its assets and their potential, as flagged by its “Critical Mineral Exploration” investor presentation in April. In that document Reach laid out its principal rare earths, niobium, lithium and manganese projects in the Gascoyne-Murchison region and its Murchison South gold project in WA’s Mid West region, near Paynes Find.
Over the past two years, the company appears to have been primarily focussed on its other assets further to the north-west in WA, however it had referred to its “Primrose Gold Project” (now renamed “Murchison South”) in a corporate presentation in mid-April last year.
Both presentations refer to the company’s maiden 2021 JORC-2012-compliant inferred mineral resource estimate for Blue Heaven, amounting to 1,035,000 tonnes at a grade of 3.2g/t gold for 105,000 ounces of gold, which includes a higher-grade component of 582,000 tonnes at 4.7g/t gold for 87,000 ounces of gold.
The company believes the resource currently remains open in all directions.
Reach Resources CEO Jeremy Bower said: “The remodelling of the Blue Heaven Prospect has provided a more accurate understanding of the subsurface mineralisation and identified immediate opportunities. Target infill gaps within the revised block model will be prioritised to confirm immediate open pit mining opportunities, fundamental to the monetisation of our gold resource. The historical data review has further identified key exploration targets and growth opportunities within the broader project area.”
While Reach has been focussed primarily on its critical and battery minerals in the WA’s northern regions, the precious yellow metal contained in its Blue Heaven prospect further south has been going gang-busters and the company figures now is a good time to monetise its gold asset which it sees as having immediate growth potential.
The first step was to fully-remodel Blue Heaven using ordinary and multiple indicator “kriging” statistical methods which more accurately evaluate the sub-surface mineralisation in terms of size, shape, and orientation.
With the methods also incorporating detailed analysis of a variety of geological data sets, the new model has uncovered previously-overlooked opportunities for further project expansion.
The revised model presents a geological and statistical rendering of the existing data set and has not been intended as a revision or update of the current resource.
That will come later after other opportunities presented by the review have been assessed and most likely after more drilling to fill in the gaps and test other extension possibilities.
The new model presents a refined interpretation of the prospect’s gold distribution and enables the development of a more accurate, robust, reliable and scaleable resource model and future expansions from it.
Previous interpretations of Blue Heaven assumed gold mineralisation was mainly sub-vertical, discontinuous and spotty, with high-grade gold and quartz veins in a classic “pinch-and-swell” configuration which tends to limit continuity and tonnage.
This distribution came about largely as a result of an inappropriately-high gold cut-off of 1g/t gold grade being applied in the previous block model, possibly based solely on a prevailing gold price of the day or a consideration about how to filter out possible internal mining dilution, instead of an initial examination of the statistical distribution of gold values.
The revised interpretation from the kriged model takes a broader approach by incorporating all assay results, rather than only those above 1g/t gold and has produced a semi-continuous lower grade “cloud” or envelope of gold mineralisation which encloses high-grade zones.
That’s what often provides an overall orientation for the gross scale of mineralisation and although it inevitably yields a lower overall grade, the outer envelopes provide boundaries within which high-grade zones can be identified and they may often exist at wildly disparate orientations, such as “ladder” structures across one of the main shear axes.
Incorporation of all the gold values has ironed-out the data set, levelling-out high-grade spikes and improving continuity of mineralised zones. It has also led to a revised model which shows the overall mineralisation dipping more uniformly to the south-west and at a shallower angle than previously believed.
When contrasted with previous drilling results, the new model points to the possibility that the Primrose Fault - which separates the Paynes Find gneissic rocks from the local greenstone rocks - may actually lie west of its originally-interpreted position.
Reach sees the strongly-sheared contact zone between the gneiss and the greenstones as a significant exploration target which could host high-grade gold over potentially viable mining widths.
One RC drillhole intercepted 3m at a whopping grade of 92.1g/t gold and remains open at depth.
The grade and geology of that hole is in keeping with historical gold produced from Paynes Find, which focused mainly on high-grade gold in often glassy quartz veins within the gneiss, the main target-style for previous drilling..
Reach now plans to target gaps in the revised block model to identify previously missed mineralisation and immediate open pit mining opportunities and also to extend open mineralised zones along the Primrose Fault, particularly along Blue Heaven’s western flank where the fault’s revised position offers new exploration potential.
On a historic note, Payne’s Find is a less well-known but historic gold mining location in Western Australia. The townsite was gazetted in 1911 in the same year that the Paynes Find gold battery was constructed for crushing and recovering gold.
The town is named after the prospector, Thomas Payne, who was the first to discover gold in the area and also the first to register a lease for gold mining with the Mines Department.
Reach looks to be on a winner with its new strategy and already has a head-start on an indicative resource which appears to have some of its secrets already unpicked by well-focussed work to reveal new possibilities.
As long as gold prices continue to hover around current prices or continue their recent meteoric frenzy, the company will have plenty of incentive to plug in additional holes and unlock more of those secrets.
Is your ASX-listed company doing something interesting? Contact: matt.birney@businessnews.com.au
By Doug Bright
