Cold Gold Clutha Ltd (CGC) is seeking consents to suction-mine for gold on the Upper Clutha River from the Luggate Bridge to the confluence of the Clutha and Lindis Rivers — about 23km.
It wants to use a suction dredge that is a self-powered steel pontoon catamaran 23.9m long with a beam of 6.6m.
Consents are required from the Otago Regional Council, the Central Otago District Council and the Queenstown Lakes District Council.
Commissioners Craig Welsh, of Nelson, Rob van Voorthuysen (chairman), of Napier, and Jane Sinclair, of Queenstown, began hearing submissions on Tuesday.
Of the 11 submitters who presented their case to the panel yesterday, only one was keen on CGC’s proposal.
Phillip Wilson said he started suction dredging in 1988 and in 1992 was granted a permit to dredge at Beaumont.
Dirty water from the deepening of the Clyde Dam tail race put an end to his mining, Mr Wilson said.
He had had many years working underwater and observing areas he had earlier dredged.
When looking at those areas, it was not possible to tell they had been mined, Mr Wilson said.
The Clutha was a large, powerful and dynamic system which was continuously rearranging the gravel and rocks with every change in the river levels.
"Drift diving in the Clutha is not a quiet experience. There is a continuous clicking and clunking as rocks are rearranged, making their way downstream."
He had seen lampreys and eels go "up the spout" of his suction dredge and back into the river with no discernable effect.
Trout would appear within minutes of starting to dredge, looking for food that was disturbed from the gravel, he said.
"Suction dredging is, in my opinion, an efficient, environmentally sound way of mining."
Hawea-based fishing guide Jeff Forsee said the proposed suction mining threatened not only the health of the fishery located there but the amenity value, which were two equally important reasons tourists chose New Zealand and the Upper Clutha.
He escorted between 130 and 150 anglers each year, who paid $1200 a day, and believed that was likely to double in coming years, Mr Forsee said.
The dredge would cause significant disruption, ruin the experience for walk and wade fishers and add a level of risk for those fishing from rafts.
While the dredge had been working on the lower Clutha for some time, it was important to note the two sections of the river were very different, he said.
"The lower river is much wider and has significantly higher flows. The upper river has many braids and flows into the top of Lake Dunstan, which is a productive trout fishery in its own right."
Kayakers raised concerns about the anchor lines posing hazards in the river, especially in bends where there was no visibility before coming into the working area of the dredge.
Yesterday afternoon, the commissioners made a site visit to the proposed mining site.
The hearings are set to conclude today.
