Guard against highwall and stockpile incidents by staying aware of hazards, inspecting the areas, and controlling access to the areas.
By Tina Grady Barbaccia, News/Digital Editor
To keep your operation’s employees safe when working around and with stockpiles and highwalls, the Mine Safety and Health Administration (MSHA) offers five best practices:
• Be aware of overhanging material when loading from stockpiles and highwalls.
• Stay back from the edge and build a berm.
• Stay clear of draw points above surge tunnels.
• Always scale the highwall back.
• Never place yourself between the equipment and the stockpile or highwall.
“When looking at your pits, always look for berms on the backside,” says Pat Hayden, regional safety manager for Mountain States at Knife River. “Make sure no one is going to sneak into a pit. You don’t want a farmer or someone to come over the edge of your mine in the dark.”
On the backside of a highwall, berms must be kept in top-notch condition. “We have a 980 loader that is used to maintain a gravel berm about 3 feet high,” Hayden says. “You need at least that.”
In high-traffic area, signs should be erected to keep people out of the pit that do not belong there.
A good rule of thumb, Hayden says, is to keep people away from a highwall with the same height to distance ratio. “If you have a 20-foot highwall, people should never get within 20 feet of it,” Hayden notes.
Since 2007,MSHA reports that there have been no reported fatalities from falling off a face/rib/highwall in the metal-non-metal mining sector.
Employees also need to be aware of the highwall structure when loading from stockpiles and highwalls, especially overhanging material. “They need to watch out for material frozen in the top part of the highwall,” Hayden points out. “You can hit a frozen layer as you’re moving through the highwall. If it’s good gravel, it tends to just fall down as you mine it. But if it’s frozen or the ground has quite a bit of water in it, you could undermine the wall.”
If a highwall is visibly undermined, Hayden says, it may need to be pushed down with a loader. “The base is always going to have an alluvial plane,” he says. “Hopefully, there is material in the base.” Typically, a vertical edge cannot be seen, Hayden notes, adding, “You don’t want it to come down in a vertical piece. You want it to slough off. You hardly ever see a clean edge.”
When working close to the crest, MSHA emphasizes keeping a safe a distance because of a high potential for injury for unprotected employees in the fall hazard zone. Before an employee begins work, the highwall area should be inspected by a “competent” person. “This person goes out, evaluates the area, and determines if there are any issues,” Hayden says. “As a rule, it doesn’t matter that it’s required. You always need to look around your work area. If you have a major storm the night before, make sure highwall, guardrail, or berm conditions haven’t changed. Make sure they are still safe.”
Even if there hasn’t been a storm, when a highwall is being mined out, conditions are always changing, Hayden says. This needs to be noted. As part of the highwall inspection, he says, the person inspecting the area should ask, “What does this look like every day? Is it doing what it normally does?”
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