About 50 people watched the proceedings at the Upper Hunter Shire Council chambers.

Thoroughbred racing identity John Messara spoke strongly against the proposed mine, saying even "the perception of environmental damage" was enough to threaten the Upper Hunter's $5 billion stud industry.

Mr Messara, whose Arrowfield Stud is downstream from Bickham on the Pages River, said it was irrational to allow even one mine to be established in an area "internationally recognised as the heart of Australia's thoroughbred industry" and spoken of in the same breath as Kentucky or Newmarket

"There is no amount of compromise, or future mine planning, that could compensate for the potential harm this mining project could cause our waterways, industry, jobs and region," Mr Messara said.

He quoted an email from former prime minister Bob Hawke, who he said wanted to "add [his] voice to those" supporting the thoroughbred industry.

Other landholders and stud farmers spoke against the mine, but yesterday's hearing also took evidence from people equally adamant it should proceed.

Simon Ford, proprietor of the Murrurundi Motel, said his town was dying and urgently needed the jobs boost Bickham would bring.

Mr Ford said Bickham's experts believed the impact on the river would be "minimal" and the land involved was hard-rock country "that wouldn't fatten a flea".

Christian Paget, a mineworker with the company wanting to build the mine, said it was a good local company that "would be under scrutiny from day one".

He said that while the stud industry was valuable, a lot of the money went overseas and the pay rates for most workers were "at the minimum wage".

Yesterday's hearing opened with an address by the chairman of the Planning Assessment Commission, Dr Neil Shepherd, who said he and his colleagues were part of a preliminary process advising the Minister for Planning, Tony Kelly, whether Bickham should proceed to a full environmental assessment.

While they were mainly concerned with water issues, they were also able to take other issues into account.

Bickham water consultants Peter Dundon and Steve Perrens told the hearing there was only a limited "connection" between the mine site and the river.

Bickham director John Richards said outside the hearing that the company had done everything the Government had asked of it.