Striking Miners in Soviet Union Threaten to Flood Coal Pits : Economy: The mines could be put out of commission for months. Up to 500,000 workers have joined the walkout.

MOSCOW —  Soviet miners threatened Sunday to flood their coal pits as a desperate next step in the month-old strike that has crippled parts of the country’s heavy industry and cost the economy millions of tons of coal.

The threat to flood the mines--which could put them out of commission for months if not permanently--appeared calculated to force the Soviet government to abandon its hard line on the miners and consider making concessions.

Up to 500,000 miners in coal fields across the country have joined the walkout that began March 1, according to strike leaders. They estimate that about one-third of the country’s 600 mines are at least partially shut down.

The stoppage began largely to protest the government’s failure to fulfill promises made during the last nationwide coal strike, in the summer of 1989.

Along with their demands on salary, financial freedom and working conditions, some striking miners have added a list of political issues that include the resignation of Soviet President Mikhail S. Gorbachev and his government.

Anatoly V. Malykhin, a strike leader from the Siberian Kuznetsk Coal Basin, announced the flood threat in a speech Sunday at the Russian Federation’s Congress of People’s Deputies, the legislature chaired by populist leader Boris N. Yeltsin.

“The mines are being prepared to be flooded--miners know what that means,” Malykhin said.

“Leaving the Kremlin after this Congress,” he continued, “we’ll look around and see nothing but ashes. You know that metallurgy is connected (with mining) and after metallurgy comes machine-building, and so on and so on. . . .”

Malykhin, who called for a joint Russian-Soviet commission to deal with the strikers’ demands, refused to divulge in a later interview how many mines could be flooded.

“That’s our secret,” he said.

But a strike spokesman in the Donetsk Coal Basin, the traditional heart of the Soviet coal industry, said an opinion poll was under way among the region’s miners to gauge their support for flooding the mines or simply stopping maintenance of the pits, which would also cause serious damage.

Vladimir V. Semenin, a member of the strike committee at the Krasnoarmeiskugol mine complex, said the miners’ next step will depend on talks scheduled for Tuesday between Soviet Prime Minister Valentin S. Pavlov and strike leaders.

Strikers will flood mines in the Kuznetsk basin if the government tries to “repress” them with lawsuits or arrests, said Yegor Zorkin, a member of the strike committee in the city of Novokuznetsk.

Zorkin held out little hope on the talks with Pavlov because the prime minister has refused to discuss any issues other than the government’s 1989 financial promises to the miners. Strikers are insisting that their political demands be addressed as well.

“We will stand to the end,” he said in a telephone interview. “There is no way back for us. We understand that the Communists’ days are numbered, but another year under the Communists would mean the end of the country.”

Malykhin went even further, saying he considers those who negotiated with Pavlov to be strike-breakers.

Along with causing painful damage to an already collapsing economy, the coal strike has increased the friction between Gorbachev’s central government and Yeltsin’s Russian Federation leadership, the radical reformers who head the largest of the 15 Soviet republics.

Yeltsin supports the miners and has criticized Gorbachev for not opening talks to find a solution to the labor conflict, particularly when the strikers are mainly asking for the kind of economic freedom to run their own affairs that would fit in well with promised market-oriented reforms.

Gorbachev administration officials have condemned Yeltsin’s stance as counterproductive and asked pointedly why the federation government, if it cares so much about the strikers, has not moved to help with their housing and food supplies.

The national legislature voted last week to order the strike suspended for two months while strikers’ demands were discussed. But miners immediately rejected the ruling, saying it would only harden their resolve.

Meanwhile, the economic damage has mounted and an array of factories, particularly metallurgical plants, are reportedly on the brink of closing down for lack of coal.

Pavlov has said that the economy will be set back years by the strike, and coal industry officials have reported that at least 3 million tons of coal have been lost. Many factories may be unable to recover from the break in production, they predict.

Production of farm equipment could also be affected, officials have warned, which could reduce the country’s already insufficient food supply.