Hidden Treasure mine left unanswered questions

Friday, 22 January 2021

COLUMN: 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 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 that surprising that Jacobsen had grown up thinking he could discover his own treasure hidden in the earth.

By the time his son 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.

Joseph’s grandfather, Hans Jacobsen, had even inspired a diamond rush in South Canterbury when he claimed in 1883 to discover diamonds in the Alford Forest. Tests later revealed a small proportion of the stones were genuine diamonds, but most were of so 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 of dense shiny alloy ‘chlor gold’, and he went to great lengths not only to analyse it, but also smelt it off in his forge. His dream became no less than make 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 his 70ft by 30ft 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,

His efforts certainly seemed rewarded on March 12, 1904, when Joseph called on wife Mary to lay the first corner stone of the new works at the 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 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 Jacobson 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. Some suggestions were raised at this point that samples were being peppered.

The real trouble was, 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 sailing back from Totaranui when his boat capsized going over the Takaka River bar at Waitapu, the entire venture ground to sudden halt.

A 1907 government report on mines simply described the Hidden Treasure mine as having lain idle since Joseph’s death.

The whole venture literally fell apart overnight, and it has received no more than the odd mention in any gold mining histories written in this country ever since.

The exact site of the deserted battery is clearly marked on the Subdivision Plan for Puramahoi, drawn up after WWI to assist with allocating land for returning soldiers.

The terrain has been significantly altered since Joseph operated here at the mouth of Battery Creek. The road has been extended and the flattish island which used to exist off here has been washed away, thanks to Council rock protection put in here several decades ago.

Two railway irons driven in at the waters edge still mark where two fishing boats used to tie up (Battery Road used to be called Wharf Rd), and a concrete plinth is all that’s left of the water gates that used to dam off the tiny estuary so that the ‘water meadows’ further up stream 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 got impounded here.

Interesting how the landscape, and land use practises, can alter over a century or so. But one thing is sure, Joseph picked a prime site for his battery and smelter tucked in on the protected lee of Patons Rock peninsula.

None of Joseph’s ore samples from the Hidden Treasure are known to still exist, although it is likely looking back that tungsten was a key element. In 1958, his son Charlie Jacobsen wrote down his recall 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 reveals Jacobson as a passionate miner who believed he was onto something great.

Whether anyone will reinvestigate the lode of rich ore high in the hills above Onekaka, still locatable if you know where to go, is anyone’s guess. Maybe it was the name, but I can’t help but think Joseph Jacobsen was onto something, a true hidden treasure in the hills.