NEW YORK — Barrick Gold will try to acquire Newmont Mining Corp. in an approximately $18 billion all-stock deal that would create a mining behemoth worth about $42 billion.

Colorado’s Newmont has rejected any talk of a buyout from the Canadian miner so far and the unsolicited bid from its fierce rival appears likely to become hostile. On Monday, it appeared no closer to accepting a bid from Barrick.

In acquiring Newmont, the largest U.S. miner, Barrick would create a mining company that could be four times the size of its next closest rival.

Newmont stockholders would receive 2.5694 Barrick shares for each share they own, according to the proposal from Barrick on Monday.

Barrick shareholders would own about 55.9 percent of the combined business, with Newmont shareholders owning approximately 44.1 percent.

Barrick CEO Mark Bristow said that the two companies have complementary assets in Nevada, which includes Barrick’s mineral endowments and Newmont’s processing plants and infrastructure.

Combining the companies, Bristow said, will create $7 billion in lowered costs.

Barrick kicked off a gold mining consolidation rush last month when it acquired Randgold Resources for more than $6 billion. Newmont launched its own takeover bid in January with a $10 billion offer for Canada’s Goldcorp.

Miners are seeking to combine with other miners as gold becomes more expensive to procure. Gold prices have been on an upward trajectory for almost two decades and are up 4 percent this year, to about $1,330 per ounce.

On Monday, Barrick Gold Corp. said that Newmont should drop its pursuit of Goldcorp.

There were no signs that Newmont was ready to do that, and pointed out that Barrick made any tie-up with Newmont conditional on just such a retreat.

Newmont, in a response to the bid Monday, said the offer from Barrick was “at a negative premium.” It said that Barrick is ignoring risks of such a deal, and overstating potential rewards.

“Newmont has previously determined that Barrick’s risk and return profile is inferior on many fronts, including factoring Barrick’s comparatively ineffective operating model, poor track record on delivering shareholder returns and unfavorable jurisdictional risk,” Newmont said.

At the same time, perhaps in preparation for a hostile takeover, said, “Newmont’s proposed combination with Goldcorp represents the best opportunity to create optimal value for Newmont’s shareholders and other stakeholders.”

It said the combined company would have the largest gold reserves and resources in the gold sector and that it would lead to $265 million in annual savings.

Shares of both companies dipped at the opening bell, with Newmont falling 2 percent.