The MGTSV Mine cable of structure is that 250µm optical fiber is sheathed in a loose tube made of high modulus material, and the loose tube is filled with waterproof compound. The center of the cable core is a metal reinforcing core. For some fiber optic cables, a layer of polyethylene (PE) needs to be extruded outside the metal reinforcing core. The loose tube (and filler rope) is twisted around the central reinforcing core to form a compact and round cable core, and the gaps in the cable core are filled with water blocking filler. Double-sided plastic-coated steel tape (PSP) is longitudinally wrapped and then extruded into a flame retardant sheath into a cable.