Rock Bolt Extensometer

Model EMA-11 Overview

EMA-11 measuring anchor, also known as rock bolt extensometer, is used to determine load exerted on rock bolts. It is a precision instrument designed to evaluate anchor system forces and their distribution within the length of the bolt and hence its safety and effectiveness. A digital caliper/micrometer depth gage with a resolution of 0.01 mm is used to take readings. An electrical head assembly consisting of four potentiometric sensors is optionally available for electrical output.


Length3, 4, 6 m
Fixed points4
Borehole diameter51 mm
Anchor diameter26.7 mm standard
Loading capacity250 kN
Range± 5 mm
Resolution0.01 mm
EnclosureIP 65