CHARLESTON, W.Va. -- The nation's top mine safety official on Wednesday touted an aggressive agenda of tougher new regulations and said the U.S. Mine Safety and Health Administration would not be deterred by the failure of reform legislation last year or by the Republican takeover of the House of Representatives."We will be prepared to make our case to the public, the industry and to the Congress for the reasons these [new regulations] are necessary," said Joe Main, assistant labor secretary in charge of MSHA.MSHA plans to issue six new proposed regulations in as many months, on top of highly complex proposals that are pending to limit miners' exposure to coal dust that causes black lung and toughen standards for preventing coal-dust explosions in underground mines.Late last year, Republicans in the House defeated mine safety legislation proposed in the wake of the Upper Big Branch disaster, and the GOP takeover is expected to make Congress more likely to scrutinize any new government regulations.And MSHA already faces some criticism of the pace of its investigation into the explosion that killed 29 miners at Massey Energy's Upper Big Branch Mine, including a letter from Democratic Sen. Jay Rockefeller of West Virginia urging the agency to more frequently brief the miners' families on the probe.During a conference call meant to focus on the agency's regulatory plans, Main told reporters to expect more information on the Upper Big Branch investigation "in the next few weeks.""It's always bad to put out timelines, but we will have a new update that is more informative," Main said. "We want to get it right and we want to take the time to do that."Main has said several times that the strain of the Upper Big Branch probe has not forced his agency staff to lose focus on other priorities, such as MSHA's announced plan to "End Black Lung." But the agency's regulatory agenda still does not provide a timeline for finalizing what could be a landmark rule to tighten the legal limit on coal dust that causes the deadly disease."As we all know, the regulatory process is not something where you snap a finger and finalize action tomorrow," Main said. "It takes time."Plans for the dust rule were in the works prior to the April 5 mine disaster, and the proposed rule was issued by MSHA in late October. Public hearings are being held this month and next month, with a written comment period set to expire at the end of February. MSHA's published agenda does not list any deadlines or goals for actions beyond the end of the comment period.Last month, MSHA issued one of two proposed rules that were added to the agency's agenda after the Upper Big Branch disaster. It would require company safety exams to make note of any health or safety violations that are discovered, whether or not the company believes the violations are a hazard. The existing rule requires only that conditions the company believes are "hazards" be noted and corrected."When I see the number of citations being issued at underground mines, I think it's a bit outrageous that these problems aren't being found and fixed by mine operators," Main said Wednesday.After Upper Big Branch, MSHA also issued an emergency temporary standard that requires mine operators to use spread more crushed stone around underground mine workers to try to reduce the chance for coal-dust explosions like the one agency investigators believe occurred at Upper Big Branch. That rule -- coming after years of warnings by scientists that existing rules were outdated and too weak -- is scheduled to be finalized by June.Later this month, MSHA is scheduled to issue proposed changes to its "pattern of violations" enforcement rules and a new proposal to require mine operators to use special "proximity devices" meant to keep miners from being run over by fast-moving underground equipment.In June, MSHA is set to propose new rules to how it sets civil penalties for safety violations and to require companies to have certain types of health and safety programs. In July, MSHA says it will issue rules regarding exposure to silica dust and to require mine operators to submit additional corporate information to help the agency keep track of companies or company officials with bad safety records.Reach Ken Ward Jr. at firstname.lastname@example.org or 304-348-1702.