 An inseparable combination on mine property, truck and driver. No matter the type of material being mined and hauled, or the size and type of truck, it's the movement of material to the crusher, storage here, preparation plate, mill, railroad siding, or the reclaiming. It's this combination of driver and machine that gets the job done. This video is designed to help you the driver to better understand truck braking systems, to highlight important principles of mine haul road design and maintenance, and to show you safe procedures in the event of a runaway truck. Please note, as with all training material of this type, the procedures presented in this video should be thoroughly discussed with your instructor, and emphasis given to your truck haulage equipment and local mining conditions. I'm Mike Lawless, District Manager with the Mine Safety and Health Administration. I'm John Radomsky, System Manager, Mine Safety and Health Administration. The video that you are about to see will emphasize the need for you to maintain a good braking system on the trucks that you are operating. It will also emphasize the need for you to be constantly aware of the grades that you're operating on, as well as the type of actions that you should take in case of a runaway accident. Mike, I agree with you. The haulage trucks in use today have very excellent service brake systems. However, the steep grades that we see them being used on and the poor conditions that we sometimes encounter make it extremely important that the drivers have everything properly maintained and working. It may also surprise several of you that your chances of survival during a runaway accident are much greater if you stay with the vehicle rather than jumping from it. Mike, our experience shows that drivers who regularly wear their seatbelt have a much greater chance of surviving a runaway or any other serious accident. Maintaining your trucks in good condition, knowing what to do and when to do it is something that we all should practice. However, even that is never a substitute for good judgment and common sense. Mike, I couldn't agree with you more. Being in control of your haulage truck at all times is the key to having a safe day. Brakes are one of the most important safety devices on your truck. Before operating your truck, you as the driver must ensure that your brakes are in good operating condition. So that you can better understand how truck braking systems operate, let's take a few moments and go over some key points. Today, most off-road haul trucks are equipped with air over hydraulic systems. Many of these trucks have spring applied and hydraulic or air released brakes. These are known as fail-safe systems. These systems require hydraulic or air pressure to keep the brakes released. Therefore, a loss of air or hydraulic pressure will cause the brakes to automatically apply. Off-road haul trucks generally have one of three main types of brakes. Shoe and drum, usually air or hydraulic applied. Pressure forces the shoes outward onto the surface of the rotating drum. Caliper disc, usually air over hydraulic systems. Hydraulic pressure forces the brake pads against the rotating disc. Full disc or wet disc systems. These brakes consist of multiple discs, alternating, rotating and stationary, which operate in hydraulic oil. Hydraulic pressure squeezes the discs together. Are you familiar with the braking systems designed to slow or stop your truck? Let's look at them. The service brake, or foot brake, is the main brake for stopping your truck. The emergency brake is for use only if there is a problem with the service brake. This brake is sometimes called a secondary brake. The parking brake, which, as its name implies, is used only to hold the truck while parked. Off-road trucks are also equipped with retarders or dynamic braking systems. These systems are used primarily to slow the truck and maintain speed on grades. They protect the primary service brake system from excess heat and extend service brake life. Various types of retarding systems are used on diesel electric trucks. With retarders, it is important that you maintain specified engine RPM to ensure the retarding system does not stall the engine. Truck haulage roads are developed in the initial mine planning. Consideration should be given to grades, roadway widths, slope of grades, length of grades, curves, berms, ramps, drainage, equipment size and type, traffic patterns, and site distances. The truck manufacturer is an important source for road design information, and should be consulted by the mine operator to determine maximum recommended grades of haul roads, and truck braking distances at various speeds and loads. Use extra caution when driving on any slopes or steep grades. As mentioned earlier, roadways should not be built so steep as to require the constant use of service brakes to maintain a safe speed. If long grades require constant application of service brakes, overheating may cause brake fade and or damage to the braking system. Therefore, auxiliary retarders or dynamic retarders are usually preferred as the first means of speed control when traveling down grades. While driving over hilly terrain, be especially alert at crests in the haul road where your line of sight may be limited. Again, roads should be designed to minimize blind areas, but if such areas do exist, reduce your speed to where you can safely stop in the event you meet another vehicle. Besides the grade of haul roads, roadway width is another design consideration. One way traffic is best because it reduces the risk of collisions. The least desirable condition is two-way traffic on a one-lane road with pull-offs for passing. This is especially hazardous where visibility is limited. As you can see, this requires frequent stopping and the risk of collision is increased. It also increases wear and tear on trucks and haulage cycles are usually slowed. How is adequate room for passing on the haul road determined? Roadway widths are based on the width of the largest trucks using the road. Berm width is not considered as part of the roadway width and should be provided in addition to these recommendations. Width recommendations are, single-lane roads should be twice as wide as the truck, thus providing a clearance of one-half the truck's width on either side. Multi-lane roadways should provide this same clearance from the edges of the road, plus one-half the truck's width between traffic lanes. For example, a two-lane roadway should be at least three-and-a-half times as wide as the truck. Additional roadway width is needed on curves to provide necessary clearance, particularly where there is two-way traffic. Also, all roads should be sloped to provide proper drainage. The very nature of mining causes the location of mine roads to be continually changed. Hall roads require persistent attention. Be alert to motor graders, dozers, or other equipment maintaining the roadway. Adverse weather conditions also play a major factor in the maintenance of haul roads. Until the surface mud can be removed by the graders, rain or snow can turn an otherwise gentle grade into a mud-slinging hazard. Of course, on dry days there isn't enough moisture in the ground to keep the dust down, so water trucks make their rounds from pumping stations to the haul roads throughout the mine. Berms or guardrails are required on the outer banks of elevated roadways, where there's a drop-off steep enough to cause a vehicle to overturn. The minimum height of berms must be axle-high to the largest vehicle using the roadway. This mid-axle criteria should also be applied to guardrails or other roadway barriers. Safety berms should be constructed so as to provide resistance to a truck going over the edge, but you should not rely on berms to stop your truck. You should use berms as visual indicators. Use them for guidance to let you know that you are within the safe zone of the haul road. Berms will serve to alert you that you are near the edge and to assist in redirecting your truck back onto the road. Remember, a truck striking a berm at a right angle is more likely to travel over or through it than if the wheel stayed parallel with the berm. Berm restraint is provided from a combination of the tire penetrating the berm and then riding up the berm material. The face of berms should be cut at an abrupt angle to raise the wheel after it hits the berm and to minimize any ramping effect that could permit the truck to ride over the berm. The berm works by giving you the opportunity to keep your truck from leaving the roadway. If berms are repeatedly cut along the inside, the stability of the berm will suffer. The base of the berm must be wide enough to maintain the height of the berm. Berms require continuous attention to maintain adequate width and height. Roadways should be wide enough to provide for adequate traffic lane widths plus the berm. In cases where the roadway is not wide enough, berms are sometimes extended over the outer slope. This does not give you a berm that is as strong as one that is built on a solid base. Berms may have small openings to provide for drainage, which is important for proper maintenance. Boulders are sometimes used as a form of berm, especially at mines where they are a natural product of the operation or in areas where large rock formations are present in the over berm. If you drive on haul roads where berms are made of large boulders, be aware that an impact with them could possibly cause injury. Smaller boulders used to minimize impact will slide a considerable distance and therefore should not be placed close to the edge. For these reasons, boulders are not the best means of providing vehicle restraint. Guard rails are sometimes used in locations where the installation is permanent, such as at a mine entrance. Guard rails may also be found where the road is not wide enough to install berms. Guard rails must be substantially constructed and suitable for the type and size of equipment being used. Center or straddle berms are used in addition to edge of road berms or guard rails to provide a greater degree of safety. Center berms cannot be wider than the distance between the wheels of the trucks. They can also serve as an excellent means of traffic control to prevent head-on collisions. Escape or runaway lanes are sometimes used on steep grades and are the best restraint system in terms of minimizing injury and equipment damage. A loose base material, which a truck can sink into and the steep upward grade are effective ways to stop runaway trucks. A runaway truck is potentially one of the most dangerous hazards that you may face as a driver. But there is much you can do to prevent runaways. And if you do experience a runaway, there are ways to protect yourself. A key precaution is to buckle up and stay buckled up whenever you're driving. Seat belts can keep you in position to control your truck. Seat belts keep you out of the windshield in collisions. They protect you from being ejected from the can or thrown about inside the can during a rollover. And they can keep you alive. Your truck shouldn't be overloaded at any time, especially if you're running on steep grades. This is something that can contribute to a runaway. If the load or grade exceeds the manufacturer's design specifications, your truck's braking ability and your margin of safety are reduced. Always obey posted traffic control signs along the haulage roadway. They are there to assist and remind you of safe operating procedures. As you operate your truck, drive defensively and think ahead. Picture the road ahead and mentally review your options in the event of an emergency. Keep in mind the location of other traffic, escape lanes, banks, berms and turnouts. Plan ahead and you will be better prepared to react quickly. Before you start down a grade, slow down. Select the proper gear and be sure your retarder is functioning. Don't depend on your retarder and service brakes to slow your truck down after you've started down the grade. If your brakes were to malfunction, you can easily lose control of your truck. Generally speaking, a loaded truck should travel down grade in the same gear required to travel up grade when loaded. This rule of thumb will vary somewhat depending on conditions and equipment. If you start to lose control of your truck, don't panic. Apply your retarder or dynamic retarder systems. If your service brakes have failed, use your emergency brake. Pull near the bank. Stop and turn your wheels into the bank. Set your parking brake and summon help. If your braking systems fail to stop your truck, don't jump out. Are there any center berms, escape lanes or other options to slow you down? Use these berms or lanes as soon as possible. Your chances of survival are much better if you stay buckled up and stay with the truck. Well, the haulage equipment seems to be the most dangerous because you're always moving. The most dangerous time is probably when it freezes or starts freezing and the road gets a little slippery. The worst part of driving is when it first gets wet. Then it gets what they call greasy and it slides. And in the winter time, if it's bad, you know, we take the grader. We got gravel stuck on the side of the road here. We take the loader, put them down on the ice. Well, generally we got a thing called a retarder. It retards the back half of the truck. You know, when you're driving on the red road instead of using the brake, you use it. And give it fuel all the same time to keep it under control of the front wheels. Because if you make sure the brakes and the brakes are on all four wheels, it'll cause the front to lock up too and they have trouble guiding. There's a lot of different road conditions that we have. If the slick roads or whatever, that they could turn the truck into the berm and it'll keep them in the roadway. Well, we maintain all of our berms and we keep them at least half the diameter of the largest vehicle. They might carry a high berm, but then things will go over. Chats in all of our safety regulations that they all wear their seat belts. With seat belts, the policy with our company, as you wear them, when you're on mine property and in our equipment. When I operate my hauler, I'm always got my seat belt on.