This item of New Zealand’s engineering heritage was recognised as part of the IPENZ “ Engineering to 1990” project, which the Institution organised to help celebrate the country’s sesquicentenary in 1990. Heritage recognition IPENZ “Engineering to 1990” project The dredge buckets in Cromwell Town Centre, Cromwell represented the development of bucket dredging from the “Shine No 1” in 1900, to one of the world’s largest, the “Austral Malay” in 1940. It was abandoned and became partly submerged in the river, but was salvaged and restored in 1978 for display in the town. One of the few relics from those days is a dredge operated from a barge on the nearby Taieri River in 1896. Patearoa, 17 kilometres south of Ranfurly, had its goldrush in the early 1860s.

Gravel scooped up by a chain of buckets was washed over sluice boxes and gold tables and the waste or tailings deposited at the rear of the dredge, something that environmentalists would not tolerate today. The Kanieri, the last of the 150 gold dredges that worked the West Coast, was still operating on the Taramakau River in 1990.

In the boom period of dredging, about that time, efficient dredges secured as much as 1,000 ounces of gold in one week’s working. It is considered to have been the greatest assembly of gold dredges the world has ever seen. This success was followed several years later by another pioneer – “The Fourteen Mile Beach Dredge” – which was the first electrically-operated dredge in the world driven by a three-phase alternating current supply.īy 1900 there were 187 dredges at work among the gravels of the Clutha. The dredge was a complete success, the electrical equipment performing its work faithfully. This dredge operated on the Upper Shotover River, Central Otago, power being supplied at 1,300 volts to operate the plant on what proved to be the first electrically operated gold dredge in the world. The former of these, “The Sandhills Dredge”, was designed and put into operation in 1889–90 by RC Jones who later became one of the founders of the firm Turnbull and Jones. The first successful gold dredge was commissioned through the vision and perseverance of Sew Hoy of Sew Hoy Big Beach Mining Company and was built by Kincaid and McQueen, Dunedin.īoth the first electric dredge and the first to be electrically-operated from a three-phase alternating current supply were built and operated in New Zealand. Important changes however, have been the introduction of steam dredges about 1882, and electric dredges in 1890, and the accidental but very profitable discovery at the very end of the century, that often there were rich gold-bearing deposits concealed beneath a hard layer which was apparently the bottom of the river bed. Five years later the bucket type of dredge was introduced, and this, in various forms, has been used ever since. The earliest “spoon-dredges” were employed in 1863 and for a time they won a considerable amount of gold with very simple appliances. Amazon destruction rose to its highest levels in 15 years between 20 when an area more than half the size of Wales was lost.By means of dredges, wash-dirt was obtained from the beds of large rivers. The extent of the impunity,” tweeted Sônia Bridi, a celebrated Brazilian journalist known for her coverage of the Amazon.Īndré Borges, another journalist whose story helped expose the mining flotilla, tweeted: “We are witnessing, in 2021, a goldminers’ uprising with all the aggressiveness of the days of discovery.”īrazil’s multimillion-dollar illegal mining industry has intensified since the 2018 election of Jair Bolsonaro, a far-right nationalist who backs the wildcat garimpeiros who trawl the Amazon’s rivers and rainforests for gold.Īs many as 20,0000 garimpeiros are believed to be operating within the supposedly protected Yanomami indigenous reserve in Roraima, one of nine states that makes up the Brazilian Amazon.ĭeforestation has also soared under Bolsonaro, who has stripped back environmental protections and been accused of encouraging environmental criminals. “Just look at the audacity of these criminals. There was outrage as footage of the riverine gold rush spread on social media. But when you see a scene like that it makes you feel as though the Amazon has been thrust into this spiral of free-for-all. I was born here and I’ve seen many terrible things: so much destruction, so much deforestation, so many illegal mines. “It’s like a condominium of mining dredges … occupying pretty much the whole river.”Īguiar added: “I’ve been working in the Amazon for 25 years.

“We’ve seen this kind of thing before in other places – but not on this scale,” Aguiar said of the hundreds of rafts he saw hoovering up the Madeira’s riverbed near the towns of Autazes and Nova Olinda do Norte. Dredging rafts operated by illegal miners on the Madeira river, Brazil.

Gold mining dredge