Michigan State Grants Mine Safety Training Newsletter Vol.2 1999

Highlights Inside

Manager - Dave Carlson 906/487-2453, Email dcarlson@mtu.edu Mining Engineering Department
Mary Ewert - Clerk 906/487-2272 Michigan Technological University
Program Director/Department Chair - Francis Otuonye 906/487-2610 Houghton, MI 49931

Contact Dave Carlson at the phone number listed above for assistance with setting up a safety training workshop. Contact Mary Ewert for locating suitable videos and other training materials or handouts for your in-house workshops. If we can't answer your safety-related questions we will find out or put you in touch with someone who can. See our internet home page at the address listed above.

Program Updates

Winter Workshops A Success. The 4^th Annual MSHA Winter workshops were held during February and March as planned. Topics discussed included Dust and Noise Control, Haulage and Machinery Safety, Outside Contractor Safety, Electrical Safety, Confined Space, Record Keeping and Most Commonly Cited Standards. Participation was good with the numbers attending as follows: Marquette 41, Gaylord 83, Ann Arbor 69, and Grand Rapids 55.

Program Personnel Developing New Supervisor Safety Manual. An outline for a new Supervisor Safety Manual was presented to Program Advisors at an Advisory Board Meeting held in Gaylord on February 10, 1999. Board members approved of the outline, and work on the details is planned for the upcoming summer -- after the bulk of our annual refresher training is completed.

Some Recent MSHA Changes that May Affect You

Currently, the law requires new miner, newly employed experienced miner, annual refresher and task training. However, congress has not allowed MSHA to cite certain surface operations which do not train. Starting sometime after October 1, 1999, MSHA will be able to begin issuing these citations. MSHA is currently developing a curriculum for training these operations which fits their needs better than the curriculum currently spelled out in Part 48 of Title 30 CFR. MSHA also announced recently that supervisors are required to take annual refresher training.

A recent change was made to the definition of a "newly-employed experienced miner". A newly-employed experienced surface miner is now one who has at least one year of experience working in a surface mine. A "newly-employed experienced underground miner" is now one who has at least one year of experience working in an underground mine. Mention is no longer made of how recent the experience must have been.

Are Your Employees at Risk of Being Electrocuted?

Rewards and Costs for Unsafe Behavior: Electricity is everywhere. We use it in our homes, offices, and shops, usually with little concern about associated hazards. Over the years we have conditioned ourselves to overlook safety precautions by having "done it that way before" without serious or fatal consequences. We've saved money and time by not purchasing available safety equipment and by not taking precautions, and we may be convinced that the precautions are not really needed. But luck usually runs out in time, and when this happens the consequences may be serious - even fatal.

Many of the costs associated with serious or fatal accidents or injuries in the workplace, which, among other things, include the reputation of management, are not covered by the company's insurance policies and, for many businesses, such an event is the "straw that breaks the camel's back". Where serious or fatal accidents do not occur, MSHA citations can be very costly running into the thousands of dollars, and when accidents do occur the fines are usually much higher. For these and other reasons, it is important to take proactive safety steps to minimize or eliminate known electrical hazards. As with other hazards, there are a number of relatively inexpensive steps that can be taken to ensure the safety of workers who use electricity.

Understanding Electricity: A little under-standing of electricity can go a long way toward helping us make the right choices. We may think of electrical current flowing through a wire or other conductor the same way we think of water flowing through a pipe. Pressure upstream in the pipe causes the water to flow through the pipe. With electricity, voltage (may be thought of as electrical pressure) causes the current to flow through a conductor (the pipe). The higher the pressure in a water line, the higher the flowrate of water through a pipe of a given size. Likewise for electricity, the higher the voltage, the higher the flowrate of current (measured in Amps) through a conductor of given resistance (measured in Ohms).

We can restrict the flow of water in a pipe by putting sections of narrower pipe in line or by turning a valve in the direction that closes it. In the case of electricity, some materials are better conductors (have less resistance) and some are poorer conductors. For example, metals are usually good conductors of electricity, and nonmetals are usually poor conductors. Even a very low voltage will force a lot of current to flow through a metal wire. However, the voltage has to be quite high to force significant amounts of current to flow through a nonconductor like rubber. Most dry woods, plastics, rubber etc. are relatively poor conductors (good insulators), and it takes a lot of voltage to cause significant current flow through them. However, there is a need for caution, because some items made from these "insulating" materials are reinforced with steel fibers and electrical leaks can also develop in other ways allowing current to pass through the material.

The presence of moisture greatly increases the danger of electrocution. Don't be deceived by the fact that water itself is a relatively poor conductor. Extremely small amounts of impurities found in all water supplies make it a very good conductor.

Typically in our daily lives, we come into contact with 120 volt ac (alternating current) electrical appliances and tools. Although 120 volts is not considered to be high voltage, it accounts for a large number of electrocutions each year at home and at work. For a 120-volt electrical outlet to supply current, it must be connected to the current source by two wires. One of the wires is the hot wire and the other wire is the neutral wire. The hot wire has 120 volts (of electrical pressure) and the neutral wire has zero volts (is connected to ground). If the hot wire were connected directly to the well-grounded neutral wire, current would flow so fast that it would rapidly heat up the wires and start a fire (often referred to as a short circuit). A properly-sized circuit breaker in line detects excessive current flow, and opens up stopping the flow before the wires overheat. Electrical appliances in a circuit provide resistance to current flow, which reduce the flowrate to where the circuit breaker doesn't trip.

How Electrocutions Occur: Electrocutions usually occur when a person who is in good contact with the earth contacts a hot wire. The amount of current flowing through the person's body to the earth depends on how good the contact is between the person's body and both the current source and the earth as well as how high the voltage is. If the person has wet hands the person makes better contact with the source. If the person has wet feet or is standing in water, on wet ground or concrete, the person makes better contact with the earth. In these cases, only a very low voltage (perhaps 30 volts) could result in electrocution. Higher voltages cause enough current flow for electrocution, even when the person's hands and feet are dry and make only poor contact with the current source and the earth. Current flow through the person's body upsets the heart rhythm and causes cardiac arrest.

The use of electrically-powered handtools is often associated with electrocution. An electrical fault can develop in a hand tool resulting in contact between the hot wire and an exposed part of the tool. The tool looks no different than before and works fine. I may even have been using the tool in this condition for weeks, months, or years if: 1) I have worked only on dry wood floors, 2) I have always had well-insulating rubber boots on when I used the tool outside or in the basement, or 3) I have always worked on a rubber mat. I may, under certain circumstances, have felt a slight tingle, but thought nothing of it.

But then my unlucky day comes and I decide to use the tool on the garage floor. My garage outlets are not GFCI-protected, I don't have time to find a rubber mat to stand on, I have leather shoes on, and the floor is damp. "Zap" - and its all over with -- or is it? If I am really lucky, my neighbor is watching and knows enough to run over and immediately pull the plug and begins CPR. This keeps oxygen flowing to my vital organs while a paramedic is called. When the paramedic arrives, he uses a defibrillator and attempts to restart my heart.

The above situation could occur most any-place where the proper precautions are not taken. Any electrically-powered motor is capable of developing a ground fault at any time. If an electric motor on a conveyor, for example, develops a ground fault, a person standing on the ground and touching any point along the conveyor framework may be electrocuted.

How Electrocutions Can be Avoided: Let's examine the handtool electrocution in more detail to see what steps could have been taken to prevent it. The hand tool case is made of a nonmetallic substance and I have been assuming all along that it is double insulated. However, closer inspection shows that the words "double insulated" are not written on the tool, so this protection is probably not available as I already learned the hard way. Even if the tool was originally double insulated, it may have lost its double-insulation protection, by being dropped, handled roughly, or by getting wet.

The third or ground prong on an electric-powered hand-tool plug is a fair indicator that it is not double insulated in that double insulated tools don't need the third prong. The ground wire in the cord from this third prong connects to the exposed part of the tool. When plugged into the electrical outlet, this ground prong connects the ground wire in the tool's cord to the ground wire running from the outlet to the main electrical panel. At the main electrical panel this ground wire is connected to the same block that the neutral wire is connected to and it is also at zero volts. The ground wire, therefore, provides a current path from the body of the tool directly to ground. When this ground wire is intact and a ground fault develops in the tool, the direct connection to ground results in an immediate high rate of current flow from the tool body to ground, opening the correctly-sized circuit breaker and shutting down the power, thereby protecting the operator from electrocution.

Our examination shows that the third prong on the tool's plug is intact so we must look for other reasons for the tool not tripping the circuit breaker once the ground fault condition developed. These may include:

First we will make a continuity check to ensure that there is electrical continuity between the ground prong on the plug and the exposed metal parts on the tool. This test is easy to make using a $20 meter and should be made on a regular basis and especially after a tool has been dropped.

Next we will check to make sure that the ground socket on the outlet has a good connection to the neutral block on the main electrical panel. This test should also be made at regular intervals.

For a 120 volt ac circuit, we can use a simple tester which is purchased from most any hardware for about $5. The tester, looks like a three-prong plug with three lights on the back. To use it, we simply plug it into the outlet. Depending upon which combination of the three lights are on, the tester reveals either: 1) an open ground, 2) an open neutral, 3) an open hot, 4) the hot and ground are reversed, 5) the hot and neutral are reversed (reverse polarity), or 6) that the outlet is wired correctly. This testing device will usually also have a small button which, when pressed indicates if the outlet is protected by a properly-working ground fault circuit interrupter (GFCI). Pressing the button trips a correctly-working GFCI, which must be reset to resume current flow.

The tester can be used to determine if extension cords are good by first plugging the cord into a correctly-wired outlet, then placing the tester on the opposite end of the cord. Because the outlet has already been tested and found to be wired correctly, the indicator lights will now determine if the cord is good.

Contrary to what many people think, reverse polarity can also be a serious safety concern. Thus the current to electrical appliances is usually switched on and off where the hot wire enters the appliance. Turning the appliance off removes any contact between the hot wire and the appliance. However, if the hot and neutral wires are reversed in the outlet, the hot wire runs all the way through the appliance with the switch off. In the case of an electric toaster, for example, I can be electrocuted by using a fork to retrieve a piece of toast, even if the toaster is off.

The ground wire serves the same purpose in higher voltage circuits such as those that are used to operate most processing equipment and is absolutely essential for safety. Thus it is prudent for the operator to make regular inspections to ensure that all motors have a sufficiently large wire connecting the frame of the motor back to the ground connection in the electrical panel and that the resistance between the motor and the panel block is less than 1 ohm. Otherwise the circuit breaker will not trip in case of a ground fault. This inspection should also ensure that the correct size and type of circuit breaker is in use.

The Ground Fault Circuit Interrupter (GFCI): The requirement that GFCIs always be applied when electrically-powered hand tools are used is another prudent step an employer can take. GFCI protection is offered by using special circuit breakers located in the electrical panel or by using GFCI-protected outlets (having test and reset buttons). When a tool is plugged into a GFCI-protected outlet, the GFCI continually monitors the current flowing into and out of the tool. When a ground fault develops and a person's body begins conducting a portion of the current to the earth, the GFCI will trip and stop the flow of current. Only 0.005 amps of current flowing through the person's body will trip the GFCI and this amount will not harm the person.

The GFCI, which protects even where there is no ground wire, is unique in being the only single device designed specifically to protect people. A GFCI should be tested often by pushing the test button to make sure it trips or, where a test button isn't handy, simply plugging in the above-mentioned tester and pushing the button to see if the GFCI trips. If the GFCI trips it is working correctly, and no third plug prong is needed for protection.

While only a few of the hazards in dealing with electricity have been discussed here, taking the precautions suggested will be a significant step toward eliminating electrocutions in your workplace.

Traditional Safety Approaches Have Merit, But are Probably Not Effective

The following information was obtained from SafetyCurrents<JOYR@coastal.com, Volume 3, Number 12, 1999 -- a weekly electronic newsletter by Coastal Training Technologies Corp., 3083 Brickhouse Court, Virginia Beach, VA 23452

1-800-823-0412.) Careful consideration of the points made could be the beginning of a successful and productive safety and health program at your mine site.

Traditional approaches to safety have merit, but their long-term effectiveness is limited, according to Sam Gualardo, director of corporate safety and health for Niagara Mohawk. Speaking at a recent

ASSE symposium, Gualardo offered these comparisons:

The key, says Gualardo, is to get managers selling safety to line supervisors. "Managers influence the norms, beliefs, and assumptions

that influence safe behaviors. These guys can change the world," he says.

Michigan Holmes Group to Participate in and Hold Meeting at Michigan Safety Conference

The Great Lakes District Council (GLDC) of the Holmes Safety Association will again participate in the Michigan Safety Conference to be held at the Lansing Center in Lansing on April 20 and 21. Two presentations will be made by GLDC. The first will be a 2-hour presentation by Dean Tahtinen and Jim Wade, of Work-Safe Company located in Petoskey, MI, starting 9:30 A.M. April 21 and entitled "Back Injury Basics (Physics, Anatomy and Prevention)." The second will be a 1.5-hr presentation by Ron Gebbie of Michigan Federal OSHA Safety Consulting Inc. located in Canton, MI starting 12:30 P.M. on April 21 and entitled "Hazard Awareness Training". GLDC Presentations are under the Mining Section of the Construction Division. A GLDC membership meeting will also be held at the Conference although the time and location have not yet been announced. Contact Joe Gentry at 517/595-6101 ext. 259 if you plan to attend.

While a GLDC Summer meeting is planned involving a half-day technical session and a tour of a mine site, neither a date nor a location has been set.

National Holmes Group to Hold Annual Meeting in St. Louis, MO June 2-4, 1999

The annual business meetings of the National Joseph A. Holmes Safety Association and the Holmes Safety Association will be held at the Adams Mark Hotel in St. Louis, Missouri on June 2-4, 1999. These meetings will be hosted by the Department of Labor and Industrial Relations, Division of Labor Standards. The agenda includes a technical session with presentations on important safety and health topics which will be of great interest to participants. To register, contact Mica Baldwin of the Division of Labor Standards, Mine Safety & Health, PO Box 449, Jefferson City, MO 65102 (Phone 573/751-3403 ext. 246 or Fax 573/751-3721). The cost is $125 per person.