机译:岩石特征同时钻孔和应用屋顶锚杆钻探地面条件评价
Department of Energy and Mineral Engineering Pennsylvania State University University Park PA 16802 USA;
Mining Engineering Department Hacettepe University Ankara Turkey;
Department of Energy and Mineral Engineering Pennsylvania State University University Park PA 16802 USA;
J.H. Fletcher&Co. Huntington WV USA;