Ten weeks after L&M Mining's gold dredge at Earnscleugh Flats near Alexandra sank, the vessel's refurbishment is nearing completion for a mid-April resumption of work.
In the interim independent environmental monitoring results of the dredge operations, including water, air, noise, dust and discharge monitoring, have been given a tick of approval in a quarterly report on operations.
The dredge, which weighs up to 850 tonnes when laden with gravel, sank in late January and has since been refloated and hauled ashore for refurbishment, understood, but not confirmed, to be worth several hundred thousand dollars.
L&M Mining owner Geoff Loudon said yesterday when contacted he expected the refurbished plant to be ready to start up again in about 10 days.
''I'm pleased to be able to say that we were able to keep all our [35] employees engaged during the shutdown,'' he said.
The $3 million Earnscleugh Flats start-up operation is one of the country's largest alluvial (sedimentary) gold-mining operations and is capable of processing about 150cu m of gravel an hour.
During the past year until the sinking, the dredge had returned on average about 750oz of gold a month, from an estimated total gold resource of about 110,000oz - which could take up to four years to work through.
In a quarterly report from last month, released to the Otago Daily Times by the Earnscleugh Project Liaison Committee, independent facilitator Karin Bowen said L&M had updated the committee on the dredge refurbishment. In mid-February the plant was refloated, dewatered and beached for repairs, which were ''nearly complete'', she said.
''During this time some planned refurbishment has also been carried out and the unit has been converted from using power generated on board to mains power,'' Mrs Bowen said.
L&M Mining first began at Earnscleugh in early 2010, initially with a smaller dredge to assess the commercial viability of the prospect, before moving to full dredging operations in early 2011.
The committee had met monitors Beca Infrastructure and Engen Consulting, which reported on environmental monitoring results for the third quarter of the 2012-13 year, Mrs Bowen said.
Aside from monitoring, the resource consents granted by the Central Otago District Council and Otago Regional Council contained 132 conditions.
During this quarter none of the resource consent limits had been exceeded for insoluble dust deposition and ''total suspended particulate concentrations''.
Groundwater, surface water and discharge water were also monitored and showed full compliance with the limits set by the resource consent, she said.
The results of noise monitoring showed levels were within consent limits, but there was discussion about truck noise at the mine on some mornings.
