Testing and Results
The traditional pull out tests currently used for rock reinforcement testing, is not considered an effective tool for the detection of compromised rockbolt systems used for ground control in underground mining and civil construction industries. Where it is still acknowledged that the pull out test has an important role to play in determining critical bond lengths for static and quasi static ground support designs, it does not provide an underground operation or Civil operation with any reassurance regarding its bolts integrity, which could have been compromised during installation or affected by in-situ aggressive conditions.
Services:
- Corrosion Detection
- Rock Reinforcement Integrity Testing
- Resin / Grouting Quality Control
- Site Testing
The Mod-Shock System for Mining and Civil
The Mod-Shock integrity testing is a Quality Control geotechnical risk management tool / test which eliminates good bolts and identifies bolts that may have some deficiency in the sense of length, not being grouted/resin properly and if it has been compromised through corrosion damage. The test is a cost effective method and thus can test a large number of bolts/tendons in a short period of time.
The system has been used for over 15 years in carrying out testing of long length steel rods, either as strand or solid steel bars in Australia and some parts of the world.
MOD-shock delivers:
- A risk management tool with visibility into the (correct installation and) integrity of the mine support system
- Continuous progress monitoring
- Customized reporting and feedback
- Cost management
- Assist Suppliers / Mines to perform better
- A unique system in Africa
Testing and Results
Testing
The test is carried out on site using equipment including a notebook, A/D converter, a transducer and tapping device. The transducer is held against the bottom of the test bolt, the program is informed that a test is about to take place. The plate is struck 3-5 times with a hammer. When a satisfactory signal is received by the computer, the next bolt may be tested.
Test Results
The test results will be categorized as follows
Category 1
A perfect bolt in perfect rock conditions, this will rarely occur.
Category 2
A bolt which we consider is serviceable in that it has good anchorage, good load transfer along the length of the bolt and reasonable rock/grout/resin contact.
Category 3
A bolt that has some deficiencies in reduced anchor strength, poor grout/resin/rock contact or loss of bolt section. The remarks section will identify the possible source of the deficiency.
Category 4
A bolt that has either failed, is loose or at a point where additional load on the bolt could lead to failure, or a loss of bolt section which is critical.