The mysteries of the Hidden Treasure Mine
GERARD HINDMARSH
It remains one of the most enigmatic mining ventures ever to be carried out in Golden Bay, perhaps the whole of Nelson province.
Was it bona fide, or a deluded fantasy promising overstated returns? One thing is for sure – all the credit for the Hidden Treasure Mine and the associated battery and smelter goes to Joseph S Jacobsen, whose early death by drowning in 1905 put an untimely end to the promising venture.
It wasn’t surprising that Jacobsen had grown up thinking he could discover his own treasure hidden in the earth. By the time he was a teenager, his father had taught him all the basics of mining and assaying, imbuing in the boy a keen sense that the country’s untapped mineral wealth was just out there for the finding.
His grandfather, Hans Jacobsen, had even inspired a diamond rush in South Canterbury when he claimed in 1883 to have discovered diamonds in the Alford Forest. Tests later revealed that a small proportion of the stones were genuine diamonds, but most were of such low grade that they were of ‘‘small value’’.
Joseph’s early prospecting caused him to wander near and far around Golden Bay’s hinterland. But his eureka moment came in the mid-1890s, when he located a lode of a strange, dense ore high on the hillside above where the quarry of the Onekaka Ironworks would later be set up.
He genuinely believed that he had found a hidden treasure. To him, that ore became the basis of a new type of metal which had not yet been discovered anywhere else in the world.
Almost certainly, of course, it was an alloy – gold with impurities of tungsten, platinum, iridium or copper, all of which are present in the area.
Joseph called his find ‘‘chlor gold’’, and he went to great lengths to not only analyse it, but also to smelt it off in his forge. His dream became no less than making a new, super-hard alloy specifically suitable for the coinage of the entire British Empire.
His enthusiastic claims got the venture off the ground with a hiss and a roar. Revenue generated from the sale of 6000 shares sold at £1 each to investors in Nelson and Auckland as well as locally was used to construct a 21-metre by 9m building housing the stamper battery and rudimentary smelter works, situated ‘‘not far from the mouth of the Puremahaia River’’.
Battery Rd, which runs off Patons Rock Rd, remembers the location of his plant today. A sledge track running up a spur between the Otere and Onekaka streams connected the mine to the battery.
Joseph’s efforts certainly seemed rewarded on March 12, 1904, when he called on his wife Mary to lay the first cornerstone of the new works at a ceremony for investors and invited guests, after which ‘‘the visitors adjourned to a large tent, and were ‘‘regaled by the Company with liquid and solid refreshment’’.
Local man Rowden Soper spoke of how the ore was no longer ‘‘the product of a brain of a fool’’, while another praised Joseph for persevering despite discouragement from all sides. John Squire also got up to congratulate him on his 10 years of ‘‘persistency’’ against the doubters.
Prospects were looking bright indeed just a few months later, when Joseph returned from a trip to Auckland, where he’d had his samples assayed by a mining expert by the name of Mr Bastard.
His verdict, 50 ounces of gold to every ton of ore, was nothing short of fabulous. Even one ounce per ton is considered payable. However, some suggestions were raised that the samples were being peppered.
The real trouble was that Joseph had set up the venture entirely on his own initiative, with no-one else involved even remotely coming near his skill set and knowledge about the project.
When tragedy struck on October 2, 1905, and Joseph was drowned while sailing back from Totaranui – his boat capsized going over the Ta¯ kaka River bar at Waitapu – the entire venture ground to a sudden halt.
A 1907 government report on mines simply described the Hidden Treasure mine as having lain idle since Joseph’s death, and it has received no more than the odd mention in gold mining histories written in this country ever since.
Battery Rd, off Patons Rock Rd, remembers the site of the Hidden Treasure’s stamper battery, tucked into the protected lee of the Patons Rock peninsula.
The exact site of the deserted battery is clearly marked on the Subdivision Plan for Puramahoi, drawn up after World War I to assist with allocating land for returning soldiers.
The terrain has been significantly altered since Joseph operated at the mouth of Battery Creek. The road has been extended, and the flattish island that used to exist has been washed away, thanks to council rock protection put in several decades ago.
Two railway irons driven in at the water’s edge still mark where two fishing boats used to tie up (Battery Rd used to be called Wharf Rd), and a concrete plinth is all that’s left of the water gates which used to dam off the tiny estuary so that the ‘‘water meadows’’ further upstream could be flooded to encourage early spring growth. Trenching that went nearly all the way up to the existing State Highway 60 delivered the fresh water which became impounded here.
It’s interesting how the landscape, and land use practices, can alter over a century or so. But one thing is for sure – Joseph picked a prime site for his battery and smelter, tucked into the protected lee of the Patons Rock peninsula.
None of Joseph’s ore samples from the Hidden Treasure are known to still exist, although it is likely that tungsten was a key element.
In 1958, his son Charlie Jacobsen wrote down his memories of the ore: ‘‘It was something like platinum to look at, very heavy. You could put it in a furnace for three days and nights and take it out, and it was the same weight when you put it in. It could be rolled out thinner than a tissue of paper, and had a ring like a piece of steel. I saw my father dissolve a bit in some acid, let it settle in a powder, then put it in a crucible and bring it back to the original metal . . . we used quite a bit for fishing sinkers when we could get it without my father knowing.’’
Local historian Pat Timmings, of Patons Rock, now deceased, took a great interest in the Hidden Treasure. His inquiries revealed Jacobson to be a passionate miner who believed he was on to something great.
Whether anyone will reinvestigate the lode of rich ore high in the hills above Onekaka, which is still locatable if you know where to go, is anyone’s guess. Maybe it was the name, but I can’t help thinking that Joseph Jacobsen was on to something – a true hidden treasure in the hills.
Joseph’s dream became no less than making a new, superhard alloy specifically suitable for the coinage of the entire British Empire.