Tender For supply of geo technical instruments - instrumented rock bolt of 22mm dia 2 point 4m length 9 gauge pairs plus 10m lead , vibrating wire stress meter for 38mm borehole soft rock coal measure formation , 4 way roof extensometer , 2 way roof extensometer , read-out unit of instrumented rock bolt, stress meter and extensometers , dual height telltale , auto-warningtelltale awtt , datalogger , setting tool of stress meter