Virginia Chief Mine Inspector Harry D. Childress, who is directing the state's investigation into a June 21 mine explosion that killed seven miners, said today he will immediately sell his nearly $19,000 worth of stock in the company that owns the mine to avoid the appearance of a conflict of interest.

Childress' decision was immediately welcomed by Gov. Charles S. Robb who, according to a spokesman, "commended him for taking this action, which may not be in his best financial interest right now."

Robb, who had appointed the former Clinchfield Coal Co. official to his post last year, is "fully supportive of Harry," said press secretary George Stoddart. "He's going to stay on the job."

The statements came after The Washington Post reported that Childress owns 1,162 shares of stock in the Pittston Co., Clinchfield's corporate parent, which he accumulated through employe stock-ownership and savings plans during his 10 years with the company. Despite a provision of state mining law that prohibits coal stock ownership by mining inspectors, Childress said he had kept the stock last year because the office of State Attorney General Gerald L. Baliles had advised he did not have to sell the stock.

The 31-year-old Childress had insisted that there was no conflict caused by his holdings because he would investigate Pittston and Clinchfield operators "the same as I investigate any others."

Following the disclosure of his Pittston stock holdings today, a top United Mine Workers official and several key legislators called on Childress to either rid himself of the stock or step down from his $35,000-a-year post.

"The potential for conflict of interest would have been obvious and massive," said State Sen. Ray Garland (R-Roanoke). "Should the man continue on the job? The answer is unequivocally no."

Childress said that, although he had talked to Secretary of Commerce and Resources Betty Diener several times today, he had reached his decision to sell off his stock on his own and without any pressure from Robb's office.

"I didn't want to cause problems for the governor, and I didn't want anyone to doubt my sincerity in enforcing the mining laws," he said.

Childress said that he had instructed his broker to sell all his Pittston stock this week, but noted that this would cost him money. Most of the stock was acquired when it was selling for about $25 a share, he said. Pittston's closed today on the New York Stock Exchange at $16.25.

As Virginia's chief mining inspector Childress heads a 25-person agency that inspects all 624 coal mines in Virginia for violations of state health and safety laws. He said today he will continue to head the state's investigation into conditions at Clinchfield's McClure Mine No. 1 that exploded last month in the worst mining disaster in Virginia in 25 years. Childress, who had previously served as Clinchfield's assistant superintendent at the mine, said that actual on-site inspections and interviews would be conducted by his staff.

"I still feel I have a job to do for the state, and I'm going to do it."

Most critics aimed their fire today less at Childress than at the attorney general's office for advising him in a letter last year that he did not have to sell his stock. Senior Attorney General Francis Lee had defended that letter on yesterday, saying that, while state mining law forbids a "mine inspector" from owning coal stock, it makes no mention of the chief of the division of mines, who is known as the chief mining inspector.

"That's like saying Sitting Bull wasn't an Indian because he was the chief," said State Sen. Joseph V. Gartlan (D-Fairfax), one of many critics of Lee's reasoning.

"The attorney general's office has raised hair-splitting to an art form," said Gordon C. Morse, director of Common Cause of Virginia.

Attorney General Baliles today released a letter to Robb in which he defended Lee's interpretation as being proper according to the precise language of the statute, but acknowledged that this "brings an anomalous result." He recommended that the language be changed by the legislature as a result of the Childress case.

"I do not know why inspectors are subjected to more stringent requirements than their supervisor," Baliles wrote. " . . . and I am unable to discern why such a legislative result is appropriate."

Others said the case underscores the weaknesses of the state's conflict-of-interest law, which was rewritten last year at Baliles' request. Under the new law, considered a modest improvement by its advocates, a state official is not deemed to have a conflict unless he owns more than 3 percent of a company's stock or receives annual income from the firm of more than $10,000.

Baliles noted in his letter that neither applies to Childress because his 1,162 shares of Pittston compares to about 37 million outstanding shares in the firm, "an infinitesimal fraction of the company."

The conflict law is "full of holes," said Common Cause director Morse. "It's pretty outrageous."