Chris Cannon, a training manager with VISTA Training, offers the following tips to maximize safety when using hydraulic excavators directly on slopes:
Adhere to recommended operating ratios – The operator's manual for most heavy equipment will list safe operating ratios for working directly on a slope. "It's very important not to exceed that," Cannon stresses. "A lot of operators will ignore that and say, well, I know my machine. But you have to remember, if you encounter a rock or a stump or some loose material and you lose footing, that machine will probably slide. Once the edge catches on a point on that hill or on the base of the hill, it's probably going to go over – it's going to roll."
Take weather conditions into consideration. "If you're working in wet conditions, obviously, you can't work on as steep a slope as the manufacturer states," says Cannon. "It's sort of like people driving in bad weather. There's a speed limit, but if it's slippery, you can't drive the speed limit."
Pay attention to track position – When working on a hill, the tracks should be positioned straight up and down the slope. "You should never have your tracks going parallel to the slope because if you start to slide, once the edge catches, it's going to tip the machine over," Cannon points out. "If the tracks are going up and down the slope, if something catches, you're just going to roll over it."
If possible, create a terrace or bench for the excavator to dig from then position the sprockets inside of the slope next to the hill. "When you're climbing the hill, you want your sprockets to be in the back," says Cannon. "But once you're level, you want to have the sprocket, the heavy part, toward the side of the hill."
Take care during slewing – When slewing material, keep the bucket and stick close to the machine and close to the ground. "As you're bringing it around, you want to control your speed because momentum on a slope can be a dangerous thing," says Cannon. "If you're taking material from the highest part of the slope and transferring it to the lowest part, this is one time where you don't want a full bucket."
As you slew over the side, the swing motor is being used to lower the material instead of the boom. "In an extreme condition, where you have maybe a 1:1 slope, the swing motor, which is the weakest part of the machine, is working double duty. It won't be able to handle a full bucket of material safely if you're moving it too quickly," says Cannon.
Smaller is often better – "No matter what piece of equipment you're working on, you have to maintain a stable center of gravity," says Cannon. "You're going to be more stable with a smaller machine on a slope."
A compact excavator with a dozer blade is especially suited to slope work. "You can lower that dozer blade on the slope below you and it will help to stabilize the footing so you will be less inclined to tip or slide," Cannon asserts. "Another advantage of a smaller excavator is some of them have frames where the angle of the track can be adjusted up to 15 degrees, so you can actually sit on a mild slope and have the top of the machine level."