Wheel loaders must have buckets wider than their tire width to protect their rims. This reduces their linear breakout force, resulting in a longer work cycle time and smaller bucket loads. And because of an excavator's greater breakout force, it is ideal for loading compacted material.
Wheel loaders typically require more than twice their own length to maneuver properly. But with an excavator, limited working space is not a problem, since it does not require forward and backward travel to do its job. And tandem loading of dump trucks is easier to do with an excavator since the excavator remains parked, thus decreasing cycle times. Also, Hitachi quarry and mining excavators (except the EX8000-6) are available in both front shovel and backhoe configurations, offering a different kind of flexibility in digging and loading options.
Hydraulic excavators are stationary, minimizing floor congestion and reducing operator fatigue. This compares to the constant motion of wheel loaders, which is hard on operators and requires their attention be split between a variety of tasks.
When the footing gets poor, wheel loaders have problems. Travel and production efficiencies drop. Poor footing has little effect on excavators.
Up to 50 percent of a loader's operating expense involves tire wear. Tracked machines have costs due to undercarriage wear, but wear cycles are considerably longer and can be managed more effectively. More uptime is a big advantage of tracked machines.
Wheel loaders have a relatively low dump height making it difficult to see where their load is going. However, excavator operators sit high up and can easily see into the beds of the trucks they load. And their bottom-dump buckets make it easy to place the load precisely, saving wear and tear on the truck beds.
Wheeled loaders are obviously faster than excavators, and the ability to quickly move loaders to another location is a major benefit. However, many mine managers have found the constant shuffling of loaders to be inefficient. If loaders are constantly moving, they may not be right economic choice for the operation. Remember, excavators are not as speedy, but they can travel.