In this week’s edition of Bulls N’ Bears Big Hits, we examine some of the notable drill intersections revealed on the ASX, including Mako Gold’s 7m at 5.39 grams per tonne gold from 87m at its Napié project in Côte d’Ivoire.
We also take a close look at other interesting drill hits from last week as reported by Sunshine Metals at its Liontown West resource in Queensland and West African Resources at its Kiaka gold project in Burkina Faso.
We usually look for “big hits” in earlier stages of exploration so we can follow the geological and decision-making thread leading to decisions to drill a particular hole. We don’t usually look at grade control results, because by the time that stage of drilling comes around, the target has already been defined and the drilling is usually at high density in a mineralised zone and the results don’t often vary too much between holes.
But this week, we include the West African venture in a place we haven’t touched on before in this column and where that company’s big hit is one of several thick, near-surface, high-grade gold results from grade-control drilling at its Kiaka South project.
The Kiaka deposit also reminds us that quite a few Aussie explorers are working in various African gold belts and some of them are producing massive results from remarkable resources.
So, let’s dive in.
Napié project - Côte d’Ivoire, Africa.
Hit: 7m at 5.39g/t gold from 87m including 1m at 31.15g/t gold from 93m.
Mako jagged this hit in its recent 1200m reverse-circulation (RC) scout drilling program at its Tchaga North prospect, part of its 90 per cent-owned 224-square-kilometre flagship Napié project in Côte d’Ivoire.
The company views the hit as pointing to a possible high-grade gold target with the potential to enhance its existing 1 million ounces of gold in its Tchaga and Gogbala deposits. The two deposits host a combined 868,000-ounce global maiden gold resource.
The Napié project sits in the West African Birimian greenstone belt that hosts more than 70 deposits carrying more than 1 million ounces of gold.
Tchaga lies 8km north-east of Gogbala, while the subject drillhole is a further 7km north at Tchaga North, meaning the stretch of tantalisingly prospective volcanics comprises about 15km of arcuate strike.
The highlight drillhole sought to test below a particular zone of south-east striking, deep, open workings at Tchaga North, known as “the deep artisanal” site. It was drilled from about 40m north of the line of old workings, with a dip of about 60o on a south-westerly azimuth to a depth of 145m.
Once an area of gold mining by locals, the artisanal activity is now greatly reduced, with only a handful of miners left. That is due mainly to the groundwater table and increasingly-hard rock limiting the digging with only hand tools to a maximum of 40m depth.
Sampling around the artisanal area picked up surface rock-chip sample results above 10g/t gold, while previous sampling of mullock dumps at the site produced three best gold results of 24.34g/t, 9.47g/t and 4.55g/t gold. Other surface rock sample gold assays from Tchaga North run grades in the 5g/t to 10g/t range, while several lower-grade minnows run in the 1g/t to 5g/t range, all combining to produce a host of strong gold sniffs around the site.
This impression of gold abundance is further enhanced by results from previous limited drilling to test for north-south structures in the Tchaga North area, which picked up gold in 8m at 8.53g/t, 1m at a whopping 215g/t and 4m at 101.31g/t.
The artisanal mining zone initially appears to be the northernmost of a 6km-long trend of scattered gold working and surface sample hits in Tchaga North.
However, a further 12km-long arcuate trend of prospective volcanics continues beyond Tchaga North to the northern end of company’s tenure and includes limited past drilling at Komboro, which jagged 9m at 3.26g/t and 1m at 30.47g/t gold.
With so many positive indications, including previous high-grade rock-chip samples with results of up to 76g/t gold, 1.2km south-east of the successful subject drillhole, Mako says its various prospects within Tchaga North provide a good starting point for further drilling at depth and along strike.
Several trends of gold mineralisation were noted in current drilling of east-west structures and in previous drilling of north-south structures. Also, previous trenching of east-west structures returned gold values of 4m at 3.97g/t, including 1m at 14.8g/t and 4m at 1.79g/t including 1m at 5.34g/t gold.
The company plans to investigate further and says it will include some diamond drilling to unravel complexities that seem to be associated with multiple mineralising phases and crossing structural trends.
Ravenswood Consolidated project, Queensland.
Hit: 6m at 8.54g/t gold and 0.8 per cent copper, 2.7 per cent zinc and 1.32 per cent lead from 73m.
The RC hole is one of six put into the company’s Liontown West resource shallow infill drilling for a total of 1117m during a program that was completed mid-last month.
The highlight result is a secondary intercept included in an 11m primary intercept carrying 4.9g/t gold, 0.52 per cent copper, 1.73 per cent zinc and 0.91 per cent lead. Drilling targeted a gold-copper zone defined by historic broad-spaced campaign that produced best results of 5m at 27.9g/t gold and 1.7 per cent copper from 20m, 5.7m going 8g/t gold from 76.3m and 3m running 13.8g/t gold from 89m.
Sunshine has now added the latest highlight to its bag of treasures that have arisen from a series of impressive intersections this year, including 20m at 18.2g/t gold, 16.2m at 4.5g/t gold and 1.1 per cent copper from the footwall zone of the Liontown resource.
The headline intercept was accompanied by three other holes that nailed high-value hits – mostly good lengths in the 3m to 11m range, with gold grades between 0.44g/t and 2.6g/t and strong base metals with copper ranging between 0.3 and 1.47 per cent, zinc from 0.24 to 6.95 per cent and lead in the range 0.28 to 14.35 per cent. The results originate along more than 1km of strike extent and the company envisages further extensions will be found along the 1.6km-long footwall.
The historic, shallow drillholes are spaced at about 80m apart. The latest drilling closed down the grid to about 40m for resource estimation modelling.
The Liontown West footwall contains the gold-copper rich Carrington and New Queen Lodes, the former being mined as the Carrington Lode between 1905 and 1911, producing 28,000 ounces of gold at about 22g/t. Other ongoing work at Liontown beyond the resource infill drilling includes resource extension diamond drilling of seven holes for about 2500m at the Gap, with two of them completed.
Significantly, with respect to the Liontown resource, the Gap Zone represents about 400m of strike, only 250m to the east, but to date it has been subject to only limited drilling. It seems the mineralisation stands a good chance of being continuous between Liontown and the Gap and beyond towards Liontown East.
Accordingly, the Gap diamond drilling is planned to test around recent thick, high-grade gold-copper including 16.2m at 4.54g/t gold and 1.11 per cent copper from 319m including 6.2m going 9g/t gold and 2.52 per cent copper from 329m and a second hole also carrying good widths of respectable gold.
The company’s resource targets extend from Liontown West to Liontown East, a distance of about 1.8km at surface. They follow a 30-degree dipping body as seen in long section accompanied by a sea of handsome gold grades going somewhere between 15g/t and 30g/t gold.
The 2024 program also proposes additional testwork under Liontown East, between about 100m and maybe as far as 550m vertically below surface to resolve a few questions in the thinly-tested area.
The upshot of all the activity is a busy period of news flow through the remainder of 2024, including receiving assay results from the Liontown East, sampling of historic core and imminent first results from the Gap. All that is expected to be followed by other results, new drilling and a resource update at the end of the year, along with other metallurgical studies and various surveys.
Kiaka project – Burkina Faso, West Africa.
Hit: 22m at 7.6g/t gold from 2m including 13m at 11.17g/t gold.
West Africa’s main hit is one of several thick, near-surface, high grade gold results from grade control drilling at its Kiaka South target.
Other intercepts of similar order from the same program include 26m at 5.8g/t gold, 26m at 5.6g/t from 1m, 28m at 4.8g/t from 1m, 11m at 11.87g/t from 17m and 9m at 13.8g/t from 18m. All holes except the headline hole ended in mineralisation.
Grade-control drilling at the Kiaka South deposit has been completed for a total of 975 holes drilled to an average depth of 28m for a whopping 27,559m of drilling. The program was designed to improve management’s confidence in the interpretation of mineralisation and in gold grade estimation in the upper 20m of the deposit.
The company says results from the central part of Kiaka South are better than expected, intercepting with higher grades closer to the surface when compared to the current resource model. The drilling program was undertaken on a 12.5m-by-6.25m pattern over the northern half of the pit and on a 6.25m-by-12.5m staggered pattern in the southern part.
Results have aligned well with the company’s current mineral resource estimate and confirm that mineralisation widths generally range between 2m and 10m.
Additionally, thick zones of high-grade en-échelon mineralisation up to 20m wide have been identified in the central portion of the Kiaka South pit. It is in that area where gold grades from the program have exceeded resource model predictions – the upshot being that Kiaka South looks like it could deliver some high-grade mill feed in the early years of the mine plan.
The maiden grade-control drill program is expected to accommodate the first 12 months of the Kiaka South pit material movement and has been prioritised earlier in the mine schedule. That is because it will send higher-grade ore to the plant and also provides fresh waste material to assist with the tailings storage facility (TSF) and the run-of-mine (ROM) ore pad.
The site crew is aiming to optimise the shape of the Kiaka South open pit to increase grade and reduce the strip ratio before mining begins in the first quarter next year, with the company on track to produce 4 million ounces of gold in the next decade.
Annual production looks set to peak in 2029 at a rate of 473,000 ounces of gold, with its unhedged resources now standing at 12.8 million ounces and 6.1 million ounces in ore reserves.
In the first 18 months of ore production at the Kiaka project, the Kiaka South pit is expected to produce 1 million tonnes of ore at an average grade of 2g/t gold, significantly higher than the overall Kiaka project reserve grade of 0.9g/t gold.
In the same period, the main Kiaka pit is expected to generate a total of 9.5 million tonnes at 1.2g/t gold.
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