Yes its true! General Motors developed the Titan in response to the need for more efficient haul trucks by open pit mine operators. GM believed that a general decrease in mineral ore quality combined with a projected need to mine tar shale and tar sands would increase the quantity of ore hauled by surface mine operators' trucks, worldwide.
Terex put the 33-19 "Titan" into service with Kaiser Steel at its iron mine at Eagle Mountain, California, in January 1975.[7][8] The 33-19 "Titan" experienced frequent downtime, but over the course of its four years of service at the Eagle Mountain mine, the 33-19 "Titan" hauled approximately 3.5 million tons of earth.