The National Union of Mineworkers' president says there are no plans to merge with the UK's biggest rail union, despite holding talks on the idea.
NUM membership has fallen
NUM leaders met with their counterparts at the Rail, Maritime and Transport
(RMT) to consider pooling resources.
But the NUM's Ian Lavery said it was "absolute nonsense" to suggest the union would merge due to falling membership.
The NUM was once one of the most powerful trade unions and organised the 1984 miners' strike.
RMT general secretary Bob Crow told BBC News Online there had been a couple of meetings so far between top officials at the two unions but the talks remained "relaxed". No documents had been yet been drawn up.
He would be pushing the idea at the NUM's weekend school in Scarborough, later this month.
"We have always had a close relationship with the miners both politically but more importantly industrially because our members have always carried coal," he said.
Combining their assets could be in the interests of both unions, he said, but he denied dwindling membership of the NUM had driven the idea.
Indeed, the NUM had proposed a merger in 1995 but the RMT had decided against it, he said.
Mr Scargill was NUM leader
NUM leaders such as Arthur Scargill and Joe Gormley used to be household names but the union's 500,000 membership has dwindled to a few thousand now.
The RMT's own membership has increased to about 65,000 over recent years under the leadership of left-winger Mr Crow.
But on Monday afternoon NUM president Mr Lavery said no proposals were on the table and no further meetings were planned.
"We are probably one of the richest unions in the country," he said. "We don't need to merge with anyone."