Virginia assumed control of mine-reclamation efforts in the state's Appalachian coalfields yesterday in a federally approved move that immediately encountered criticism from environmentalists and others.

The Environmental Policy Institute charged that the change will allow further environmental damage in Virginia and encourage other states to propose similarly weak mine-reclamation regulations. Mark Squillace, a former federal official now on the staff of the Washington-based group, said environmentalists may file suit against the Interior Department to overturn the Virginia program.

In the state's southwestern coal-producing region, B.V. Cooper, president of the Virginia Mining and Reclamation Association, an industry group, complained that U.S. officials had imposed unnecessarily harsh rules on the state. "The whole tone is frustrating mining, adding expense to mining," he said.

Danny R. Brown, the Virginia official who will run the newly approved state reclamation program, expressed concern about 19 conditions set by the Interior Department, saying further negotiations are likely. "We're not saying that we like them," he said. "But certainly we agreed to them and we intend to comply . . . . We're going to have to live with it."

Interior Secretary James Watt, nevertheless, expressed confidence in Virginia's enforcement program, which was approved last week and went into effect yesterday. "This administration has restored the state to the role Congress intended," Watt said. The 1977 Surface Mining Control and Reclamation Act provides for transfer from U.S. to state control.

Mine reclamation has long been a controversial issue in Virginia, where the coal industry remains a powerful political force. Virginia challenged the federal surface mining law in court, obtaining an order that for a time barred enforcement of the act in Virginia. The Supreme Court rejected the state's claims last June upholding the law's constitutionality.

Recently, controversy has centered on what critics termed a loophole that allowed major coal-mining companies to bypass the U.S. environmental controls in Virginia. At issue was an exemption from the 1977 law for mines affecting two acres of surface area or less. Although apparently aimed at small "pick and shovel" operators, the exemption has been widely used by large coal and energy corporations, relying on contractors and subsidiaries.

In approving Virginia's program, Interior officials said they had taken steps to end misuse of the exemption. "We want that loophole closed," a spokesman for Interior's Office of Surface Mining said yesterday. Among the 19 conditions set by Interior in approving Virginia's program were tighter restrictions on the exemption and detailed reports on results.

Virginia officials also have promised to seek legislation at next month's General Assembly session to remove the two-acre exemption from the state's own reclamation law, although a spokesman for Gov.-elect Charles S. Robb said he has not yet decided whether to support the measure. Critics contend that none of the steps taken so far by either the state or federal governments will end abuses of the exemption.

With yesterday's transfer, control over Virginia's reclamation program shifted to the state Division of Mined Land Reclamation, which has grown to a staff of 40 inspectors from 17 to 20 four years ago. Meanwhile, the federal mining agency plans further staff cuts and the closing of all but one of its Virginia offices. It will retain "oversight" authority.

The shift also will clear the way for allocation of $3.9 million in federally controlled funds to Virginia in the next few months for reclamation of abandoned mines.