Stability of Powered Industrial Trucks • Stability Triangle • Longitudinal Stability • Lateral Stability • Dynamic Stability
Stability Triangle Vehicle Center of Gravity (Unloaded) B A Center of Gravity of Vehicle and Maximum Load (Theoretical) C Notes: 1. When the vehicle is loaded, the combined center of gravity (CG) shifts toward line B-C. Theoretically the maximum load will result in the CG at the line B-C. In actual practice, the combined CG should never be at line B-C. 2. The addition of additional counterweight will cause the truck CG to shift toward point A and result in a truck that is less stable laterally.
Stability Triangle Load CG Load CG Vertical Stability Line (Line of Action) Combined CG Combined CG Vertical Stability Line (Line of Action) Truck CG Truck CG This vehicle is unstable and will continue to tip over The vehicle is stable
Forklift Fatality • On July 24, 2004, a 19-year-old laborer with 8 days mining experience was injured at a crushed stone operation. The victim was operating a skid steer loader to clean spillage around the plant. He was found caught between the tilt cylinder assembly and the top front of the operator's cab. The victim was flown to a hospital where he died on August 6, 2004.
Forklift Fatality • On October 1, 2003, a 39-year-old laborer/operator, with 4½ years experience, was fatally injured at a surface dredge operation. The victim was using a forklift, near the edge of a dredge pond, to relocate the dredge's high voltage cable. He drowned when the embankment sloughed off causing the forklift to tip in the pond.
Forklift Fatality • On September 1, 2003, a 20-year-old laborer, with 1½ years mining experience, was fatally injured at a surface dimension sandstone mine. The victim was operating a fork lift when he lost control and overturned while traveling on a mine roadway.
Forklift Fatality • On December 9, 2002, a 48-year-old delivery truck driver was fatally injured at a potash operation. The victim parked his truck at the warehouse and was gathering the slings that had been used to secure the rolls of conveyor belt to the flat bed trailer during transit. As a forklift was being used to unload a roll, it accidentally dislodged another roll from its wooden cradle. The victim was struck by the roll as it fell from the flat bed trailer.
Forklift Fatality • On May 5, 2001, a 58-year old mechanic (contractor employee) with 3 days mining experience was fatally injured at a dimension stone operation. The victim was preparing to perform maintenance on the front wheel of a skid-steer loader. He had extended the boom to the full raised position and disconnected the pressure side hydraulic line for the boom. The sudden release of hydraulic pressure caused the boom to fall, pinning him against the ground.
Forklift Fatality • On Tuesday, March 21, 2000, a forklift operator was fatally injured in a surface haulage accident. The operator of the forklift was traveling on the Scale House road to a storage building to pick up an electric motor. The forklift apparently slipped off the shoulder of the paved roadway which had a 9" drop to the gravel shoulder area. When the operator attempted to maneuver the forklift back onto the paved roadway, the forklift slid sideways and rolled over pinning the victim between the front left post of the falling object protection and the asphalt roadway.
Forklift Fatality • On December 2, 1996, a mechanic with 9 years of mining experience was killed at a limestone quarry. There were no witnesses to the accident. The employee was in the process of repairing a skid steer loader and was crushed when the bucket arm on the loader came down on him.
Forklift Fatality • On September 13, 2000, a skid loader operator, age 28, was fatally injured as he either leaned over in the seat or attempted to exit the skid loader and accidentally activated the controls, causing the bucket to lower and pin him between the cross-bar member of the boom and the frame structure. • On July 19, 1997, a front-end loader operator, with 1 year of mining experience, was fatally injured at a sand and gravel operation. The victim was operating a small skid-steer loader to clean up around the plant. When he leaned out of the cab to refasten a latch that had come loose, he inadvertently pushed the pedal which operates the lift boom. The victim was pinned between the cross arm of the lift boom and the upper front edge of the cab. • December 12, 1996, a fork lift operator with 20 years of mining experience was killed at a limestone quarry. The employee was operating a fork lift when he struck a pipe that was protruding 1-foot out of the ground. The fork lift overturned causing the employee to be partially thrown from the operator's compartment and pinned under the unit's canopy. The victim died from crushing injuries.
Safe Work Procedures • Always operate within the specific capacity of your equipment. • Always look in the direction of travel. • Always think about the hazards of the route you must take before you get there. • Always operate your equipment at safe speed.