bids are invited for custom bid for services - provide and installation of dust barriers in underground white washing of roof and sides stone dusting along incline no1 and 2 belt travelling haulage and other important roadways places in seam ii iv and v at naheriya under.. - hard and durable wooden rigit frame of 4m length built from 15cm wide 2.5cm thick hard and durable wooden planks, two members of which are separated by 20cm apsrt and tied at minimum 5 places in between them and to supply them at pit top of naheriya underground mine. 4m x 15cm x 2.5cm , hard and durable wooden boards to be supplied pit top to naheriya underground mine. 50cm x 15cm x 1.25cm