Thomson Resources (ASX: TMZ) has unveiled numerous high-grade historical drill intersections for its Webbs silver and base metals project in New South Wales, as it gears up to deliver a mineral resource for the deposit this quarter.
With resource calculation underway, Thomson has revealed multiple high-grade historic intercepts with highlights of 6.33m at 735 grams per tonne silver equivalent from 74m (broken down: 566g/t silver, 1.73% zinc, 2% lead and 0.66% copper); and 6.62m at 739g/t silver equivalent from 67m (646g/t silver, 2.83% zinc, 0.45% lead and 0.38% copper).
Notable higher-grade intervals were 1.86m at 2,152g/t silver equivalent from 80m (1,725g/t silver, 3.65% zinc, 4.54% lead and 1.97% copper); and 1.81m at 2,078g/t silver equivalent from 83m (1,705g/t silver, 5.82% zinc, 0.70% lead and 1.48% copper).
A previous operator of the deposit Core Resources completed metallurgical test work on the ore in 2013 and this generated 87.3% silver recoveries, and produced concentrate with average grades of 3,468g/t silver, 18.3% zinc, 10.1% lead and 3.2% copper.
Similar to Thomson’s other projects that are along the New England Fold Belt, which spans the NSW and Queensland border region, Webbs was historically mined.
Silver, zinc, lead and copper was discovered at Webbs in 1884 and the project underwent several mining phases from then through to 1964.
Thomson noted the most significant mining phase at Webbs was between 1884 and 1901.
This was the Webbs Main target, which was mined over nine levels to a depth of 210m. During this phase 55,000t of ore was extracted with an average grade of 710g/t silver.
Thomson executive chairman David Williams said the Webbs resource will be the final estimate to be unveiled for the company’s projects that lie on the New England Fold Belt.
Minus Webbs, Thomson’s resources in the region currently stand at 40.2 million ounces of contained silver equivalent.
“When the Webbs mineral resource estimate is delivered, Thomson will have produced five new resource estimates under JORC 2012 in well under 12 months,” Mr Williams explained.
“This is an outstanding outcome from the team.”
Mr Williams added that as well as the resource estimates, the company will have a better understanding of the geological setting to for drill targeting and building on resources.
New England Fold Belt projects
Using what it describes as an “aggressive consolidation strategy”, Thomson pegged up several projects in the Queensland and NSW border region in a short period last year.
Acquisition of the Texas silver project was completed by August, with Thomson also owning 100% of the nearby Hortons, Webbs and Conrad projects.
Thomson is also earning-in to the Mt Carrington project in the region.
The assets are prospective for silver, gold, and base metals.
The acquisition of the Texas silver project included all permitted mine infrastructure along with mining and exploration licences.
Access to requisite infrastructure is also in place with the project connected to the state power grid.
Last month, Thomson completed a $2.6 million placement to Patras Capital, with funds to be used to advance its assets in the region.
Texas silver district
Thomson’s focus in this region is the Texas silver project, which is also known as the Texas silver district.
The district is 8km east of the Texas township in Queensland and 10km from the NSW border.
This district contains the Mt Gunyan, Twin Hills, and Silver Spur deposits, which have a combined resource of 11.26Mt at 56g/t silver equivalent for 19.5Moz of silver equivalent metals.
Broken down, the contained metal figure separates into 16.2Moz silver, 16,000oz gold, 18,500t zinc, 10,500t lead and 600t copper.
When the Texas silver district resources were unveiled last month, Mr Williams said the company had a clearer picture of where the higher-grade minerals were likely to be found.
“We are being careful about building the building blocks of the project with the aim of producing a robust, sustainable, long-term and commercially sound project,” he said.
Thomson’s Texas district previously produced 3.6Moz of silver from the former Twin Hills and Silver Spur mines, while Mt Gunyan remains undeveloped.
Twin Hills was mined between 2011 and 2013, with the previous operators extracting 1.9Mt at 71.1g/t silver.
Processing was done via heap leaching with up to 65% silver recoveries at the time.
Silver Spur was operated between 1892 and 1992 and is about 2km from Twin Hills.
Underground mining at Silver Spur generated 2.19Moz silver at 800g/t, as well as 690t zinc, 1,050t lead, 990t copper and some gold.
Metallurgical test work
Since acquiring the Texas deposits, Thomson has completed initial test work on Twin Hills, Mt Gunyan and Silver Spur ore.
The company has identified two processes that could deliver optimal recoveries.
Preliminary two-stage cyanide test results on ore samples achieved best overall leach recoveries on Silver Spur oxide mineralisation samples.
These results were 88.3% gold, 90.7% silver, 86.95% copper and 20.1% zinc. On the sulphide mineralisation at Silver Spur, flotation and concentrate results were 68.7% silver, 92.8% zinc, 63.2% copper and 64.4% lead.
In advancing the Texas district, Thomson expects step out drilling at Twin Hills could quickly build on the resource, with modelling indicating mineralisation is open at depth and in several areas.
At Silver Spur, Thomson noted mineralisation had been “sparsely” drilled to-date.
The company’s modelling indicates high-grade silver-zinc mineralisation is open to the north and is a priority for follow-up drilling.
However, the company’s current focus is delivering the Webbs resource, which it expects will increase its contained silver equivalent inventory.
Further into New South Wales, Thomson also owns the Conrad project which has a resource of 3.33Mt at 193g/t silver equivalent for 20.7Moz of silver equivalent.
100Moz silver equivalent target
Thomson’s strategy is to consolidate its resources in the region to exceed 100Moz of silver equivalent.
The company expects this will feed a central processing facility, with all projects within trucking distance.
Lachlan Fold Belt
Along with its exploration and development plans for the New England Fold Belt, Thomson is also active in the Lachlan Fold Belt in NSW.
Here, the company owns 100% of five projects which are prospective for tin, gold and silver.
Drilling is underway at the Bygoo tin project, which has an exploration target between 7,200t to 20,100t of contained tin.
The other projects in this region are: Gibsonvale (tin and gold), Buddigower (tin and silver), Harry Smith and Yalgogrin (gold), and Barellan (gold).
Thomson has the same strategy in the Lachlan Fold Belt to establish a centralised processing hub strategy, with the projects lying within a 100km radius of the proposed hub.