Standard Oil Co. of Indiana, joining a growing movement of oil companies out of non-oil businesses, yesterday said it would spin off its minerals, coal and metals operations as a separate company, in a transaction valued by analysts at between $1 billion and $1.6 billion.

Stock in the new company will be distributed to Indiana Standard shareholders in a method yet to be determined, according to a spokesman for the Chicago-based company, the nation's fifth-largest oil concern. The company expects to complete the move by the middle of the year.

Under the plan, Indiana Standard shareholders would receive stock in the new company, which will be known as Cypress Minerals Corp., a name derived from a company Indiana Standard bought in 1979 in its first major foray into the mining business. Shareholders would thus wind up with shares in two separate companies. There would be no management relationship or board representation between the two.

Indiana Standard was one of many major oil companies that diversified into mining or expanded their interests in the field in the late 1970s and early 1980s. The financial results of the moves were mostly poor, and the companies are now selling or closing the operations, along with some other non-oil businesses.

In recent months, Atlantic Richfield Co. has taken a $785 million write-off on much of its mining operations, and Standard Oil Co. of Ohio has all but shut down its mining division. Among non-oil diversifications, Exxon Corp. recently announced plans to sell its financially troubled office-systems division.

"This is in keeping with everything that's going on -- it's just a little more imaginative," said Sanford Margoshes, an analyst at Shearson Lehman/American Express.

Standard of Indiana has consistently lost money on its mining operations, including $21 million in 1983 and $37 million in the first nine months of 1984. But Carl Meyerdirk, the company spokesman, said it was believed that Cyprus could operate more efficiently and profitably as a separate firm. "I think it can be a considerably leaner operation as a stand-alone company," he said. The move will allow Indiana Standard to concentrate on its more profitable petroleum and chemcial operations, he said.

Analysts agreed with the latter assessment, but questioned whether shareholders would be interested in being given stock in a new, money-losing company. "My question is, what do you pay for losses?" Margoshes said. "What's an asset worth that isn't generating income."

The valuation of the Cyprus Mining assets will be important in assigning a price to the new stock and assessing the overall value of the deal. The operations to be spun off have about $1.8 billion in assets, roughly 5 percent of Indiana Standard's total assets, and analysts said the value of the deal could be analyzed by figuring the stock in the new company to be worth about 5 percent of Standard stock, discounted for the losses. Estimations of that value range between about $4 and $6 per Standard share.