mobile crushing plant. mobile crushing plants are mobile facilities that are used to crush the stones into aggregate for the production of sand required for concrete needed in the building and construction sector. mobile crushers are plants that are mostly preferred in short-time crusher plant projects, and consist of large and powerful work machines used in portable stone,concrete plants scdhec,temporary/portable crushing and screening equipment for nonmetallic minerals processing and sources exempt under s.c. regulation 61-62.1, section ii(b). interactive map of concrete plants located in south carolina . what are the emission thresholds for coverage under the general state operating permit for concrete plants?