The first miners to vote on a proposed settlement of the nation's record 88-day coal strike rejected it yesterday.

But conclusive results were not expected until today at the earliest.

With 32 of 794 United Mine Workers' locals reporting, most of them in South-western Virginia where many union officials opposed the tentative contract, the vote was 1,554 to 812 to reject it.

It was unclear whether the early returns, representing only a tiny fraction of the 180,000 miners eligible to vote on the contract proposal, were indicative of a trend.

But most of the early votes came from Virginia's District 28, which voted heavily in favor of ratifying the UMW's 1974 contract - more so than most of the districts. A union source conceded that this was not a good omen for ratification.

A close vote has been expected by union, industry and government officials. The heaviest voting is scheduled for today and tomorrow, and final results may not be in hand before Monday.

The Carter administration was watching the voting carefully, while keeping a low profile to avoid an anti-government backlash among the independent-minded miners.

The only definitive word from the administration came Wednesday when Labor Secretary Ray Marshall told reporters that the government was prepared to act "immediately . . . as early as Monday," if the miners rejected the proposal.

Sources said the government's first move would be to invoke the Taft-Hartley Act, under which the president is empowered to seek an injunction ordering strikers back to work for an 80-day "cooling-off" period. Congressional action authorizing temporary seizure of some or all of the struck mines may also be sought in combination with an injunction.

The administration's stakes in a settlement are high. President Carter, intervening directly after weeks of keeping hands off the coal dispute, forced the mine operators to accept the contract proposal a week ago yesterday under threats of an injunction and seizure. He is now virtually committed to end the strike, but administration officials worry about the effectiveness of all legal remedies in generating an immediate resumption of coal production.

The administration is under intense political pressure to end the strike. Acute coal shortages are forcing electric power cutbacks and job layoffs in a number of eastern and midwestern states, with more threatened if the contract is rejected.

Even if the contract is ratified by the 160,000 miners who work for 130 companies in the Bituminous Coal Operators Association, the main industry bargaining group, lack of a contract between 14000 UMW construction workers and mine construction contractors could prolong the work stoppage. Negotiators in this dispute are reportedly at least a day or two away from a settlement, and construction worker pickets could prevent some mines from reopening, as they did in 1974.

The first coalfield vote results came early yesterday from Local 1984 on the Oklahoma-Arkansas border, which voted 85 to 34 against the contract. "We feel like we've been sold out," said Bill Woodruff, the local's president. "We don't like it."

Local 8100, representing several small mines in eastern Kentucky, voted 155 to 29 for the pact. Chester Newsome, the local's president, campaigned for the contract in opposition to the leadership of District 28 (eastern Kentucky) and said his local's vote was probably not representative of the district as a whole. He said his members voted for the contract because "they's been out of work for three months and now they've [the government] threatening to cut off their food stamps" - which Labor Secretary Marshall said could happen if an injunction were ordered and the miners defied it.

When the Virginia locals started pouring in, the tally began tipping heavily toward rejection. As the Virginia vote was running 3 to 1 against the contract. Arvil Sykes, District 28's international executive board representative, said: "When the really militant locals come in, they'll be saying 'no' bigger than this."