Aiming at the problem of deformation and destruction of the overlying roadway of overhead-mining in very thin seam. the research methods of measuring the roadway loosening circle and 3D laser scanner to monitor the deformation of the roadway using geological radar are studied. The monitoring results show that the severe deformation of the roadway does not occur around the correspondin... https://www.thenaturalbabycoes.shop/product-category/ride-on/