At the request of the Demining Center of Ecuador, the U.S. Humanitarian Demining Research and Development Program at Ft. Belvoir, VA., undertook a performance evaluation of the Orbit Screen Model 68A and the Model 48-25 Rock Crusher, two pieces of equipment that could be used to remove antipersonnel land mines from riverbank minefields along the border of Ecuador and Peru. Although these devices could conceivably be used in tandem as a system, this evaluation focused on the performance potential of each unit to operate as a stand-alone system. A test was also conducted to see how long it would take the ASV SR-80, a small rubber-tracked loader, to process 90–100 m3 of material, spread to an average depth of about 50 cm (representing a minefield), through the orbital screener. The Quick Combo Bucket was used with the ASV SR-80. Finally, a demonstration was conducted to determine if the orbital screener and rock crusher could be used in tandem as a system.
The Orbit Screen Model 68 (Figure 1) is a stand-alone sifter that separates large material from soil or sand. Material to be sifted is first loaded into the sifter’s hopper, located at the top of the machine, then conveyed into the orbital screen. As the dish-like screen rotates, the rock and soil are tumbled within the screen, allowing soil, sand, and small particles to fall through the mesh. These smaller particles are conveyed away by the belt at the rear of the machine, creating a mound of soil and small particles. Larger objects (i.e., those objects that did not fall through the screen) are tumbled out of the screen onto a separate conveyor belt, which moves these items to a pile at the side of the machine. Various size interchangeable screens are available to suit a job’s requirements. Table 1 gives the specifications of the Orbit Screen Model 68
