Detecting the thickness of the top coal in a fully mechanized working face in advance can provide a basis for precise control of the top coal caving. which is beneficial to achieving a balance between the coal caving recovery rate and coal quality. By analyzing the principle of ground-penetrating radar detecting coal-rock interface and coal seam thickness. a ground-penetrating radar d... https://www.spidertattooz.com/Static-Nails-Something-Extra-Rapid-Repair-Nail-Cuticle-Oil-p39591/