Abstract: A mobile apparatus for treating substantially horizontal surfaces with particulate abrasive is provided with means for enhanced recovery of spent abrasive. Abrasive is propelled to the surface being treated at an angle such that particles rebound from the surface into a collection chute which attenuates the kinetic energy of the abrasive to facilitate recycling abrasive for reuse in the apparatus. Abrasive which is not recovered by its rebounding, passes to a rotating broom to be propelled into a collection bin for recycling for reuse in the apparatus.

Abstract: A method and apparatus for moving a blasting machine along a surface to be treated while maintaining a desired disposition of the blasting machine relative to the surface being treated. A support structure having a moveable boom with a blasting machine on its distal end is positioned adjacent the surface for treatment. Means are provided on the blasting machine to sense the positions of the blasting machine relative to the surface for treatment as the boom is moved through a working path. Movements of the blasting machine away from the desired disposition are sensed and compensated to adjust the blasting machine toward the intended disposition substantially throughout the movement of the boom through the working path.