Utility/diesel tram operator Joe Saunders, 44, who had 20 months of mining experience, was struck in the head and forehead by a damaged fire valve manifold under pressure that he was attempting to remove while working at Consol Energy’s Buchanan operation on January 11.

“[A] 1.5-inch bronze ball valve (quarter-turn valve) catastrophically failed, propelling the steel manifold into the miner's face/head,” the agency said in its preliminary findings.

“This fire valve manifold was originally damaged when an oversized load being transported on the adjacent mine track haulage system contacted the outlet causing it to separate from the 6in mine water supply.

“The failure resulted from the internal threaded body of the valve separating from the external threaded portion of the valve.”

The hospitalized miner’s brain activity ceased and he was removed from life support on January 18.

A second miner who was hit in the shoulder by the valve after it hit the deceased was treated and released.

To prevent similar incidents at US mines in future, MSHA stressed that all crews should stop all water flow to a pipe prior to performing work on a pressurized system and all residual pressure should be bled from the pipeline.

Also, when possible, a valve should be opened at an alternate location to ensure constant pressure relief.

To ensure safety during this process, the repair personnel must always lock out and tag out the valves.

Other best practices include:

• Never reuse components in a pressurized line that may have been damaged or compromised
• Ensure that components, such as valves, couplings etcetera used in a pressurized water system are compatible with the highest measured or expected static pressure in the system
• Implement a standard operating procedure for the design, installation, testing and maintenance of pressurized fluid systems that is consistent with National Fire Protection Association standards
• Inspect, examine and evaluate all materials that are being used during installation, replacement, or repair of pressurized water systems to ensure suitability
• Properly train all miners on the hazards associated with working on or around pressurized fluid piping systems
• Maintain safe and adequate clearance to prevent mobile equipment and machinery from contacting pressurized lines, valves, etc
• Install barriers to prevent equipment from damaging piping and valves
• Ensure adequate supervision is in place when moving oversized equipment in haulage entries.

The agency also instructed operations to install slow closing indicating valves.

“When opening a valve to put water flow into a pressurized system, do it slowly and minimize your exposure to pressurized components,” officials said, adding that slow closing indicating valves can be viewed at MSHA's belt fire suppression simulator at the National Mine Health and Safety Academy.

Federal officials encourage anyone with additional prevention ideas to submit them through its web site, including the year of the fatality and the fatality number.

Saunders’ death was the first coal fatality of 2012 and has been classified by MSHA as exploding vessels under pressure.