Tim Duddy, from Caroona on the rich Liverpool Plains of northern NSW, and nearby landholders have blockaded his farm, stopping BHP Billiton from entering to exercise its exploration rights.
Farmers want the federal government to establish an independent study of the impact of long-wall mining on the region's groundwater resources and the effect on the Murray-Darling Basin.
They are supported by their local federal MP Tony Windsor, who says the study must be completed before any exploration takes place.
It is estimated about half a billion tonnes of coal is stored under the Liverpool Plains - regarded as some of the best agricultural land in Australia - and could be mined for 60 years.
Duddy said prime agricultural land did not have any status under NSW state planning laws.
"So we're hoping that along the way, these processes will be reformed and water will be considered as a significant thing for the future of NSW," he told reporters.
Windsor said while the problem had emerged at a state level, there was a role for the commonwealth in solving it.
"If the commonwealth is serious about wanting to take things away from the states, and they're doing it with some degree of success with irrigation licences, what's the difference ... (with) a mining licence that's having an impact on the environment that they're trying to save?
"We must have the scientific knowledge before we allow these activities to occur."
Windsor has had discussions with Australian Greens leader Bob Brown about Senate changes to government legislation, presently before parliament, that amends the Water Act.
"Bob's given us an undertaking that he will look at this particular issue," he said.
