Submitters also emphasised the importance of maintaining full access to roads and ensuring overall consent conditions were complied with.
Oceana wants to open a 63ha pit called Coronation North, which could result in a two- to three-year mine life extension at Macraes, in East Otago.
Oceana has applied to construct Coronation North, extend the existing Coronation pit to 85ha and build a waste rock stack of up to 202 million tonnes, covering 197ha. The company also wants a dam at Coal Creek.
Boundary overlaps mean the company needs resource consent from the Otago Regional Council, Waitaki District Council and Dunedin City Council.
The ORC is overseeing the process, to avoid having three separate hearings.
The hearing opened in the Dunedin Municipal Chambers on Monday, before chairman Dr Brent Cowie and commissioners Colin Weatherall and Waitaki councillor Peter Garvan.
Company general manager Dale Oram has said the mining extension would contribute ''significantly'' to the economy.
There would be ''unavoidable effects'' on the environment, but the company would provide mitigation and compensation, and comply with any consent conditions.
Macraes area farmer John Harvie made a submission yesterday on behalf of community group Macraes Community Incorporated.
The group was upset at the standard of a ''poorly-constructed'' bitumen road Oceana had built as part of an earlier mining phase.
The road was ''continually rough and full of potholes'', although the company had said the potholes were due to be repaired, and some work had been done, he said.
The soil at the proposed extension site was ''quite shallow and fine'', making it more likely to be blown by wind, Mr Harvie said.
Former Waitaki district councillor Neil Roy, who has long farmed in the area, acknowledged the benefits mining had provided.
He highlighted the legal standing and wider significance of several roads in the area, including Matheson Rd and Golden Point Rd, and emphasised the importance of maintaining public access, and ensuring public input into decisions about roads.
Gold mining would eventually cease in the area but ''cumulative effects'' on much of the landscape would ''continue indefinitely'', he said.
Given the extension area's higher altitude and greater exposure to high winds, the potential for excessive dust was ''inevitable'', he said.
Dunedin environmental scientist Greg Ryder earlier made a submission on behalf of Oceana about aquatic values and mitigation options.
Galaxiid fish and freshwater crayfish were found quite widely in small waterways in the area.
The proposed Coal Creek dam would result in the loss of about 1.5km to 2km of ''small stream and ephemeral stream habitat of relatively poor quality''.
Dr Ryder had conducted surface water monitoring at the Macraes Gold Project for more than 20 years and had found water quality ''usually good'', with ''no long-term downward trend'' in galaxiid abundance.
Although nationally endangered, the fish seemed resilient in the area and further measures could enhance the remaining environment.
The hearing continues today and is due to end tomorrow.
