Industrial Hygiene in Construction

At times we get a glimpse at different perspectives. I saw two pictures this week which reminded me of what an amazing time and place we live.

Indonesia men mine inside a live volcano (I believe for gold) and will likely live to the age of 30. Link to MSN picture here.

Alternatively, I saw this corn maze.

We are blessed to live in a historically great period & location.  If given the chance, I wonder if the working men in Indonesia would vote?  Make your voice heard. Vote!

Here in the Northwest, rock crushing definately has a season…and that season is now. Road crews are getting set up and now is the time to make sure you get everything is in order…before the MSHA inspector shows up.

Below is my safety punch-list, specific to industrial hygiene:

• Training – I know it’s required for MSHA sites, but double check. Does everyone have it? What about contractors onsite?
• Water controls working & in place? The dust isn’t bad, yet.
• Air monitoring for silica – done it yet? Are you at a new location? New part of the quarry? Better do it again.
• Miner’s hearing checked (audiogram taken?). Anyone with a threshold shift? Make sure you follow up with another test.
• Are the air conditioning units working in the vehicles? – if they’re not= the windows will be down = noise levels WILL be up.
• Noise monitoring (dosimetry) performed 8-hour time weighted averages? If you don’t do it, MSHA will (maybe will be citation too).
• Is your shop done hardfacing the equipment? see my earlier post here.
• Paperwork in order?

Be safe out there!

Sometimes when I am at an employer’s site I am amazed at how hard people work and the determination and skills they muster to complete the task at hand. Other times, I realize how hard their job is on their body, health and being. Since I am in the U.S., I rarely get to see “horrific” conditions, but I know they exist.

Pictures are such a great to describe working conditions. If you have time, look at the pictures by Boston.com on coal mining around the world. For me, it is a reminder of how blessed we are to live where we do.

I was at another rock crushing site this week. This company has a mobile crusher that can crush some nice sized rocks. Which, by the way, is unique, since most crushers that can handle these size rocks take various cones, belts and screens.  Air sampling conditions were definitely not “worst case” due to morning mist and cloudy conditions for almost the entire day. However, any dust that was generated was most likely from the crusher- not gravel trucks, haul trucks, or wind. We did perform airborne silica monitoring and noise dosimetry on the crushing crew.

I did emphasize some easy, but usually overlooked, tips for the crew:

• keep the doors closed! (this reduces dust and noise)
• keep the radio and CB turned down as low as you can
• backup alarms should point to the back (not at the cab)
• wear hearing protection in high noise areas (around generators)

It’s still dry here in the Northwest and the crusher operations have been in full swing. This mobile, 2 cone crusher was just moved to the coast for about a six week project. We performed airborne respirable dust monitoring and noise dosimetry on the crushing crew. We use a 37mm aluminum cyclone to obtain the respirable fraction. If you run the pump at 2.5 Liters per minute you get a balanced sample across each size in the curve -5 um (microns) and smaller. I analyze for respirable dust, crystalline quartz and cristobalite. We’ve never found trydimite in this area.

There was visible dust coming from the crusher. However exposure might be a non-issue since everyone was either in the cabs of their equipment, or in the operator’s booth.  Silica exposure is nothing to take lightly. Here is a MSHA video on the subject titled, “What Does Silica Mean to You“. (windows media)

For MSHA noise dosimetry is done very similar to the OSHA methods. There are only slight difference between the two. MSHA has a nice fact-sheet here.

You can see one of the cones in the picture below (before it was running).

Industrial hygiene at a surface-mine rock crushing operation is primarily 2 major hazards: 1. airborne silica dust and 2. noise. (there are many more safety hazards but I will focus on IH)

Silica– this can vary due to:   the amount of silica in the rock, weather conditions, type of equipment, if water is used, and where the miners work around the crusher. If it’s a dry-day the groundmen’s silica exposure is right at the limits. Operators in enclosed booths, and loader operators are usually within the limits, unless their cab doors are open. And, as a caveat, to all of this information: you HAVE to do your own monitoring. There are just too many variables.

Noise– with only a few exceptions, noise levels (dosimetry)  are usually well above the MSHA Action limit of 85 dBA. Therefore most rock crushing operations need to have a hearing conservation program. – which for most companies is just measuring their employees hearing (audiogram) every year.  I always recommend that these companies have an active program. Rock crushers are LOUD.

MSHA inspectors, in our state, usually come out to each of the surface rock crushing sites 2x/year. I think it is great they get as many “safety” visits as they do, however, I’ve heard many complaints about the inspectors. Most complaints  stemming from silly citations that aren’t a safety issue, just a rule interpretation. But, to defend them, they have a hard job. They have to fly/drive all over the place, deal with miners, irritated owners, and make sure someone doesn’t get killed after they leave.

Mines (not just underground) can hurt people….but most people have seen that show on the news.