14/08/2026
Meet Thomas, a Thames miner
Thomas arrived in Thames in 1869 with hopes of striking it rich.
Like many miners, he didnât have a great deal of ready cash. He banded together with his mates, pooling their resources, sharing the workload and helping to protect their mining claim.
Now Thomas has brought a sample of rock from their claim to the Thames School of Mines.
He is hoping for one thing.
Gold.
A good assay could make all the difference.
Thomas has a family to feed, and there is a long road between finding gold in a piece of quartz and actually putting money in his pocket. First comes crushing and processing the quartz, then smelting and registering the gold and silver bullion, followed by sending it to the Mint in Australia where the bullion can be parted and the miners finally paid for the precious metals they have produced.
Until then, Thomas needs to keep the household going.
So he heads down to Scrip Corner with his assay results, hoping that a positive result will catch the eye of an investor with enough money to help fund the processing of their quartz.
Imagine opening the assay book and reading:
âQuite worthless.â
Or:
âNil.â
Crushing words for Thomas and his mates.
But then imagine seeing:
âGold, a good strong trace.â
Suddenly, there is hope.
So, what exactly is an assay?
An assay is a scientific test used to determine the quantity of valuable metals contained within a sample. For a gold miner, an assay could reveal how much gold and silver was present in their ore and, crucially, whether their mine was worth the considerable expense of further development.
At the Thames School of Mines, students and operators learned chemical analysis, metallurgy and modern extraction techniques in preparation for government mining certificates.
The School also provided an important service to the wider mining community. Staff performed assays for local miners and the public, testing rock, mineral and ore samples to determine their gold, silver and other metal content.
The assay room was entirely separate from the students' workrooms, providing a dedicated laboratory for this important work.
And the results mattered.
A reliable assay could influence whether a mine was developed, whether expensive crushing machinery was purchased, whether a shaft was sunk deeper, or whether an investor decided to put money into a claim.
Mining companies were bought, sold and floated on the Stock Exchange on the strength of these results. Assays provided miners, investors and share traders with evidence to help judge whether precious metals were actually present in the rock before committing substantial amounts of money to further work.
Assays weren't limited to quartz either. Tailings, concentrates and other rocks and minerals could also be tested.
A bullion assay for gold and silver could cost as little as five shillings, but its economic impact could be enormous.
A small sample of rock could potentially unlock the investment needed for heavy machinery, deeper shafts and large-scale crushing. Reliable assay results from banks, such as the Bank of New Zealand, and experienced experts helped give local and overseas investors confidence in Thames mining ventures.
And fortunately for us, the Thames School of Mines archives have preserved some wonderfully written records of this work.
Here are a few excerpts from Assay Book No. 11.
For Thomas and his fellow miners, these words were more than just a scientific result.
They could represent the difference between âQuite worthlessâ and the possibility of a very different future.
Come and see where it all happened, right here in your town of Thames.
The museum and school is open Wed - Saturday 10-4pm. 101 Cochrane street. $10 per adult, no charge for children. A self guided mineral museum tour is only $5, or browse our shop which is now situated in the Mineral Museum.
