The Texas district, which comprises the Twin Hills, Mt Gunyan and Silver Spur deposits, now contains a JORC 2012 resource of 19.5 million ounces of silver equivalent, based on a 25 gram per tonne cut-off, or 16.2Moz of silver, 18,500t zinc, 10,500t lead, and 600t of copper.
Silver is currently trading above US$25/oz. The metal has traded between $12-29 over the past five years, rising sharply since the start of the pandemic.
Texas is underpinned by Twin Hills at 10.3Moz grading 52gpt silver equivalent, followed by Mt Gunyon at 5.9Moz at 41gpt, and a high-grade sugar hit at Silver Spur with 3.3Moz at 156gpt.
While the deposits are dominated by the white metal, Twin Hills contains low-grade gold, Mt Gunyan has gold and zinc, and Silver Spur has zinc, lead and copper.
While the resource estimate took far longer to prepare than expected, when taken together with its Conrad project, south of the border in New South Wales, it has increased the company's resources to 40.2Moz of silver equivalent at 86gpt.
That number is unlikely to remain steady for long, and the company plans to deliver a maiden JORC 2012 resource for the Webbs project in the coming weeks.
Webbs has a historical JORC 2004 resource of 16.5Moz silver equivalent at 345gpt.
Executive chair David Williams said the company was going back to first principles to remodel each of the deposits within its portfolio and squeezing new insights from "the multi-millions of dollars of data accumulated by others" and new metallurgical testing.
"This has been no simple task," he said.
He said it had delivered three new resources and had defined the upside, including areas where drilling is expected to deliver higher-grade resources.
Ultimately, the company aims to develop its five deposits into a silver and base metal mines feeding a central plant somewhere in the New England Fold Belt under a hub and spoke model.
The company is also keen to locate new deposits.
Thomson believes that the 4.2Moz silver and small-scale, high-grade base metal estimated to have been produced from the Texas district is just a small slice of what could be a large, underexplored silver polymetallic region.
In addition to new resources, a large geophysics program is in progress aimed at identifying targets for a planned drill campaign next quarter that will prioritise high-grade Silver Spur style targets.
Texas last operated as a heap leach operation a decade ago, but likely underperformed.
Thomson shares have traded between A5.8c and 17c over the past year and opened up this morning 5% at 6.3c, valuing it at $35 million.