A proposed reorganization of United Mine Workers' assets authorized last week by the union's policymaking board could include the sale of the National Bank of Washington, the District's third largest bank, UMW officials said.

The union's headquarters sent out a news release quoting UMW president Richard Trumka as saying the union is in sound financial shape but faces "extraordinary expenses," including its international convention, in the near future.

The release said no specific measures were recommended in last week's board resolution other than the general authorization to "reorganize the assets and to evaluate the expenditures of the international union."

The union owns about 76 percent of the stock in Washington Bancorporation, the parent bank holding company of NBW, which has assets of about $1.1 billion.

The release pointed out that the union's constitution dictates that "no sale of stock involving the National Bank of Washington or real property" owned by the union could be made without approval from three-fourths of the International Executive Board.

The bank has been trying to raise about $20 million in additional capital but the UMW has been resistant, because any sale of additional stock would dilute the union's control of the bank. Should the UMW reduce its stake in NBW or sell the bank outright, a more diffuse shareholder base might make it easier for the bank to raise the money it seeks.

Besides the bank, major union assets include "a substantial investment portfolio, stock in the Rocky Mountain Fuel Corp. and real estate in Washington," the release said.

Officials had confirmed last fall that the union was having trouble meeting its payroll and had obtained a $2.5 million line of credit from another Washington bank--not owned by the union--to help pay administrative costs, putting up a downtown Washington parking lot as collateral.