Profile: SIRA Mining Technologies specializes in providing welded wires & meshes and chrome grinding media. Friction bolt is a high tensile steel tubular bolt roll formed int a "C" shape. Compression of the high tensile steel "C" shape into a hole diameter smaller than the tube generates a load transfer from the steel to rock. Pigtail eye bolts are threaded at one end for the attachment of an expansion unit. The other end is hot worked to form a pigtail eye bolt. They are recommended for the suspension of air, water, refrigeration and ventilation columns, as well as for electrical & telephone cables and chain type handrails. Pigtail eye bolts are available in standard lengths.