- Created: Monday, 22 October 2012 13:40
- Published: Monday, 22 October 2012 13:40
By Mark S. Kuhar
One of the easiest mistakes to make when considering a new wheel loader is assuming that you need the same size machine. The decision about the machine typically comes first and is based more on your experience than its specifications. It is usually followed by the selection of a bucket. That approach, said Doosan Product Manager Chad Ellis, is just the opposite of how you can most effectively evaluate a wheel loader for your routine work.
“Machine specifications may change over time; however, a machine’s model number may not. Jobsite conditions may also change. These two mistakes can hurt productivity because they may result in having a machine that is too small to properly handle the material, or is too large and inefficient,” Ellis said.
“The key topic in a wheel loader purchase is knowing what material you’ll be moving with it,” said Shane Reardon, Doosan wheel loader product specialist, “and then specifying a bucket and a machine that will not only deliver performance, but will be supported for long-term satisfaction.”
Prospective buyers can lower cost of ownership, Ellis suggests, by taking a closer look at those aspects, as well as attachment versatility, productivity and support. He and Reardon offer the following checklist of factors to consider when specifying a wheel loader to perform mining and quarry work.
1. Material Density Determines Bucket Choice.
A wheel loader’s bucket is typically its biggest revenue generator, so its size and capacity is important; but what it carries actually matters more than you may think. A bucket properly matched to its material and partnered with adequate lift capacity and dump height could reduce the number of passes needed to fill trucks.
“It’s important to first determine daily production targets. The next step is to look at the density of the material and match it to the size and capacity of a bucket, and then look at the machine needed to get that job done,” Ellis said. He points out that while producers may be working with multiple material densities – sand one day, rock the next – it’s important to spec the bucket based on the heaviest material it will handle. For instance, with machines designed for finish production in a quarry or mine, operators are often working with aggregate ranging from fine sand to large rock.
“It’s important to calculate for varying densities. Materials like sand that absorb moisture will be heavier wet than dry. Additionally, clean, washed aggregate densities can vary greatly from base fill densities. “Instead of free space in between the rocks, there’s mass. You need to recognize the high-end density values of material in the work environment,” said Ellis.
2. Bucket Selection Determines Machine Choice.
For mining and quarry work specifically, the two most common buckets used in the industry are rock buckets (spade nose front) or general purpose. For producers that frequently work with a wide range of material densities and need to meet certain production rates, a second type of bucket may be necessary.
“If you have a more abrasive application, you may want to look at a heavy-duty bucket that has some additional replaceable wear parts or ground engaging tools. Your bucket may need teeth or another type of cutting edge to be more productive,” said Ellis. Once daily production rates, material density and bucket size have been determined, the next step is to match a machine to that particular size of bucket. At this stage, it’s important to look at all of the machine specifications that contribute to productivity.
3. Reach, Power and Efficiency Drive Productivity.
Wheel loader productivity can be defined in a number of ways, but some of the most common metrics are machine horsepower, tipping load and lifting capacity. Optimum hydraulic performance improves cycle times, also leading to increased productivity.
Wheel loader technology has changed significantly over the past five to 10 years and operators need to make sure they know all of the features available to them to work as efficiently as possible. For example, Ellis said one of the biggest changes is arm-raise kick-out.
4. Attachments Expand Versatility.
One of the keys to getting the most productivity from a wheel loader is the investment in a quality attachment quick-change mechanism – which is optional on most manufacturers’ machines. Many more efficiencies can be gained from operators being able to rapidly change buckets or other attachments with a quick coupler from the comfort and security of a cab. Additionally, some coupler systems have been designed to eliminate greasing, requiring less maintenance and fewer replacement parts.
Doosan’s Reardon said loader-specific attachments have turned these heavy-duty machines into valuable assets for quarries and mines with their range from general, all-purpose material handling buckets to heavy rock buckets for more serious applications. Wheel loaders can also be fitted with pallet forks and grapples. “With several different types of buckets and specialty attachments available, the loaders’ capabilities can be maximized to complete a variety of projects for mining and quarry customers,” said Reardon.
5. Support Builds Long-Term Satisfaction.
Seek out a dealer dedicated to helping producers meet deadlines and minimize downtime with parts availability and maintenance. A committed dealer can recommend to a customer a parts stocking list for frequently used wear parts.
That commitment should also be demonstrated through an OEM’s ability to quickly provide parts that the dealer may not have on hand or regularly stocked. “Quarries and mines can be pretty intense applications, so dealer support and parts availability are definitely key aspects to consider,” Ellis said. These worksites can also be congested with several machines and multiple rock processing and loading/unloading areas. For this reason, Ellis points out the significance of a loader’s visibility from the cab. Some manufacturers also assist operators with rear-view cameras for enhanced visibility when maneuvering in reverse.
With a growing emphasis on the Environmental Protection Agency’s emissions standards with interim Tier 4 (iT4) regulations designed to reduce nitrogen oxides (NOx) and particulate matter (PM), it’s more critical than ever to follow wheel loader manufacturers’ guidelines for service intervals. On some machines it will also be critical to strictly adhere to the proper use of specially formulated API CJ-4 engine oil and ultra-low-sulfur diesel (ULSD) fuel to avoid costly repairs. “Dealerships will be the most knowledgeable and qualified to meet iT4 technologies and their maintenance requirements,” Ellis said.
Ellis recommends one final piece of advice to producers considering wheel loaders: “Make sure you’re not just buying the same thing you’ve always bought. Take the time to fully evaluate each purchase,” Ellis said. He adds that OEMs understand the magnitude of an owner’s equipment investment. “Customers should look at the total cost of ownership from maintenance and fuel efficiency to the overall production of the machine,” Ellis concludes.
Material for this article courtesy of Doosan Infracore Construction Equipment.