Increasing efficiency with support equipment

Why three support equipment pieces are in the spotlight

Support equipment is in the spotlight, and for good reason. Fine-tuning your fleet means choosing the best of all equipment, not just crushers, screeners, and earth-moving equipment. While those assets are clearly key players, looking at things that may not be top of mind (water tanks, specialty off-highway haul trucks and rear eject material spreaders) can be an effective way to improve productivity. Examining these aspects of equipment not only makes fiscal sense, but it can also be a determining factor in keeping an operation up and running efficiently and safely.

Water tank technology

How equipment operators haul and apply water can significantly impact an operations bottom line. These water trucks, primarily used for dust control, are designed with several factors that affect their efficiency. These factors impact uptime, maintenance, efficiency, and safety. Traditionally, round water tanks are the most common. They get the job done but not without challenges. The tank’s curved sides raise the water’s center of gravity, making the tank smaller than the truck can handle and the truck less stable when navigating haul roads. To mitigate the instability, operators often avoid filling their tanks completely. This means they need to refill more frequently, thus contributing to added downtime and increased fuel consumption as they backtrack to the water source. Alternatively, water tanks with square corners minimize churning and often have a larger capacity by simply not rounding off the sides of the tank. They also maximize productivity and operator safety due to their box-shaped structure, water baffles and water metering systems. The design also lowers the unit’s overall center of gravity, enhancing stability and allowing drivers to safely fill the tank to capacity. The box-shaped structure hauls about 20% more water than rounded tanks, resulting in time and cost savings. To minimize surging, some tanks feature sophisticated water control systems that use baffling running from floor to ceiling as well as along the complete length and width of the tank, resulting in full compartmentalization of the water. Almost all water tanks feature baffles, but many have large holes cut out to provide maintenance personnel access to the individual compartments. Within the outer compartments, some manufacturers install side-surge stabilizers along the walls to prevent water from rolling or churning. The number of compartments can vary between tanks. For instance, a 221,447 litre tank might have 42 or more individual compartments. To offer the best level of water compartmentalization, these baffles require holes to allow water to flow freely throughout the tank, but they need to be small enough to prevent water from surging during use. To address this, some water tanks fea-

The box-shaped structure of some water tanks makes it possible to haul more water than rounded tanks. CREDIT: PHILIPPI-HAGENBUCH

ture access doors that are about as tall as an average-sized worker to provide a more advanced solution than simply a hole near the ground in the baffle walls. These baffle doors, which technicians walk through easily, practically eliminate the need to crouch down while they maintain the tank, and the doors remain shut while the water tank is in operation, further restricting water movement between compartments. To allow technicians into the tank for maintenance, some manufacturers incorporate external doors, which can provide fresh air and natural light throughout the tank after opening all the external and baffle doors. When the tank is empty and the inside needs servicing, technicians simply enter the tank and open the baffle doors. This system offers easy service and maintenance, allowing technicians to access the inside of the tank safely and easily. Having complete and easy control over their tank’s water output gives truck drivers control over their safety on haul roads. For instance, individually controlled spray heads help water truck drivers optimize their water usage as well as minimize the chance of oversaturating haul roads, which can create slick driving conditions.

Overburden body design

On the surface, it may appear as though truck bodies do not deviate much from one design to another, but each truck’s design is created with safety and efficiency in mind. New truck body designs being used to move overburden within mines now address two major concerns that miners expressed. First, the designs have virtually eliminated the loafing effect. Second, they minimize material carryback, ensuring the bulk of the load is dumped the first time for greater efficiency. With a significant amount of load over the rear axle, the dumping motion of a truck body not professionally designed to combat material loafing oftentimes causes the front of the truck to lift off the ground. The entire weight then releases at once, slamming the truck and its driver back to the ground. This pro-

cess stresses both the truck chassis and the driver. Several modifications now move truck bodies from standard dumps to proficient machines. First, the shape of the truck bed has been redesigned. Traditional truck beds are parallel-sided, forming a chute for the material to release all at once without breaking up. This often causes the truck to rock with the sudden weight on the rear of the bed. By tapering the sides of the truck and making the end of the truck bed wider than the front, the overburden and other materials are given an opportunity to spread out while exiting the truck body. Material is further broken up by angling the back third of the body floor down and raking the edge of the floor away from the center point. By taking the floor away from the underside of the loaf, it is forced to break apart and exit the truck body with less force on not only the truck chassis, but the driver, who is not jolted as greatly within the cab. Additionally, many materials, when transported in truck beds, adhere to the truck’s surface and fail to release when dumped, so it takes a joyride back at the expense of the company. As much as 30% of a truck body’s volumetric capacity can stay behind through added carryback, making for a significant decrease in productivity. The answer to carryback problems lies in both the design of the truck body and the materials used within and outside of the body itself. Coating key parts of the truck body underside with hydrophobic paint will produce what is known as the “lotus effect.” Moisture within the haul material prevents it from sticking to the hydrophobic surface, like the water-repelling characteristic of a lotus leaf. As a result, it is impossible for anything to remain on the truck. Comparable results can be achieved within the body when strategically using hydrophobic and oleophobic steel liners to minimize material carryback.

Material spreaders on rear-eject bodies

Spreading materials may seem like a simple concept, but it is one that involves a great deal of variability and potential for lost efficiency. Material spreaders can be used to build haul roads, for road safety in the winter by spreading sand or gravel across slick and icy roads, and in other areas that require dry, solid materials to be discharged and broadcast. Typical material spreaders operate in a passive mode by using steep slopes to move the material from the body to the material spinners. This results in unsafely raising the vertical center of gravity. Even though the units have vibratory devices on them, the material still tends to bridge, adversely affecting the operation of the equipment. There are also safety concerns when crew members must manually address the material clogging up within the highly sloped bodies, often requiring them to get into tight, confined spaces. An updated option involves an active system, which uses a rear-eject body that horizontally pushes material towards the back of the bed and into a cross auger that delivers the material to broadcast spinners. CMJ

Josh Swank is vice-president of sales and marketing for Philippi-Hagenbuch.

MINING EVOLVES IN REAL TIME

KEEP UP WITH THE KEEP UP WITH THE

REQUEST YOUR FREE SUBSCRIPTION canadianminingjournal.com/subscribe