New rules making it much easier for states to rewrite strip mining regulations to suit their needs became final last week--the latest step in the Reagan administration's drive to revise the regulations under the Surface Mining Act.

Under the latest change, states' laws and regulations governing strip mining only have to be "as effective as" the federal government's rules; in the past they had to be "no less stringent than" federal standards.

Environmentalists view the changes as the most dangerous so far in the administration's efforts to loosen the law's red tape; the Interior Department's Office of Surface Mining says they will give the 16 states with their own rules more flexibility in meeting local needs.

The shift was one of President Reagan's campaign promises and among changes fervently demanded by mining state politicians, who say the Surface Mining Act was written to control the gross water and air pollution of eastern mines but is not applicable to the scarce-water practices at huge western surface mines.

The change will also allow miners to do more self-policing at a time of severe state budget crunches and vastly reduced federal spending for that task. Similar arguments have been made for other recent and future shifts: agency reorganization and job cuts, the halving of the surface mining office's enforcement budget, easing of mine spoil disposition rules and bonding requirements, and an overall rewrite of reclamation rules.

L. Thomas Galloway of the Center for Law and Social Policy said the state rule change "makes everything a lot fuzzier" and allows for much weaker regulations overall. Indiana and Virginia have already filed proposals that are much weaker than would have been allowed previously, he said, although the proposals have not yet been approved.

"Whether they the Office of Surface Mining intended to or not -- and we believe they did -- they've clearly sent a signal to the states that they can send in weaker programs, which is what they're doing," Galloway said.

For example, he said, Virginia proposes that mine operators be allowed to send a signed letter certifying that a rule violation has been abated, rather than requiring a state inspector to visit the site and certify the correction. The state would also grandfather in operating approvals for many existing structures that under federal guidelines would have to be upgraded.

"We are not weakening the regulations. We are actually making the regulations more practical and more applicable because we are allowing design to be site-specific," said James R. Harris, director of the surface mining office.

The final regulations are more detailed and give clearer definitions than proposed rules published in April, partly in response to environmentalists' complaints.

In the earlier version, it appeared that states would have been permitted to alter their regulations at will until Interior decided the state had gone too far in undercutting federal guidelines. Now the burden of proof is clearly on the state to show that its proposed changes leave its rules "as effective as" the federal regulations.