ACARP ACARP ACARP ACARP
Underground

Development Of New Testing Procedure For The Assessment Of Resin Performance For Improved Encapsulated Roof Bolt Installation In Coal Mines

Underground » Strata Control and Windblasts

Published: September 17Project Number: C21011

Get ReportAuthor: Naj Aziz, Jan Nemcik, Peter Craig, Robert Hawker | University of Wollongong,

In underground coal mining, the resin bond between the rock bolt and the strata is one of the critical elements of a roof bolting system, yet the Australian coal industry does not have an agreed standard for bolting system evaluation. A program of field and laboratory studies was undertaken to examine various factors influencing the load transfer mechanism between the bolt, resin and rock.  The entire study used M24, 21.7 mm diameter X-grade Jennmar JBX bolts and the standard Orica fast setting resin. A series of Short Encapsulation Pull Tests were carried out in three mines. These mines were Baal Bone, Tahmoor and Gujarat NRE No.1. Additional studies included the evaluation of the anchorage performance along sections of bolts installed in steel tubes and variations in the strength properties of resin depending on sample dimensions. Factors of importance considered to affect bolt installation in strata include; borehole diameter, resin annulus thickness, installation time (including bolt spin to back and spin at back), the effect of gloving and its impact on installation quality and load transfer variation along the length of the installed bolt. 24 bolts were installed at each of Baal Bone and Tahmoor mines, and 16 bolts installed at Gujarat NRE No.1 mine. Installation of bolts in steel tubes was carried out at Springvale Colliery and subsequently tested in the Wollongong University Laboratory. The summary of the field studies found that:

· Bolts installed in holes over-drilled by 50 mm resulted in relatively higher load transfer capacity for the given installation time;

· Bolts installed in 27 mm diameter holes performed better than those installed in 28 mm holes;

· In some cases over-spinning was detrimental to the load transfer capacity of the installed bolt;

· The influence of gloving was reduced with over-drilling;

· Strength properties of resin tested at different length to diameter ratios did not vary considerably. In general, the length to diameter ratio of one was found to be a convenient dimension; and

· Consistency of the strength values obtained from testing resin samples was dependent on the methodology of resin mixing and casting.

Various laboratory procedures and testing resin and grout properties tests were evaluated as suggested by British and South African standards. Special emphasis was directed to determination of the following resin and grout properties:

· Uniaxial Compressive Strength;

· Young's Modulus of elasticity;

· Shear strength;

· Creep characteristics.

The results from this evaluation revealed that some aspects of the British standards have shortcomings in sample preparation, testing and presentation of the results. Therefore, a new sampling and testing procedure has been developed as part of this study. Laboratory tests indicate that the proposed testing method is reliable, repeatable, easy to conduct and produces meaningful results when compared to underground tests. The new testing procedure is considered to be acceptable for testing resins used in Australia.

An e-newsletter has also been published for this project, highlighting its significance for the industry.

Underground

Health and safety, productivity and environment initiatives.

Recently Completed Projects

C29009Control Of Transient Touch Voltages During Switching

There have been an increasing number of electric shock incidents rep...

C29025Effectiveness Of Shotcrete In Underground Coal Mines

The primary objective of this project is to quantify the effectivene...

C34019Longwall Bretby Cable Handling Monitoring With Fibre Optics

This project examined the potential of using fibre optic sensing tec...

Underground

Open Cut

Safety, productivity and the right to operate are priorities for open cut mine research.

Open Cut

Coal Preparation

Maximising throughput and yield while minimising costs and emissions.

Recently Completed Projects

C33053Improving Centrifugal Dewatering Via Modelling And Analysis

The aim of the project was to develop a model for screen bowl centri...

C33042Coal Quality Borecore Methods Amalgamation Guide

Sampling and testing of borecores for coal quality outcomes has a lo...

C34050Hand Held Sensor For Real Time Measurement Of Fluorine Mineral Contamination In Coal

The project's objective was to create a new type of hand-held se...

Coal Preparation

Technical Market Support

Market acceptance and emphasising the advantages of Australian coals.

Recently Completed Projects

C34059Coke Reactivity With CO2 And H2O And Impacts On Coke Microstructure And Gas Diffusion

With the global shift to low-carbon ironmaking, partial substitution...

C33066Washability And Distribution Of Sulfur And Trace Elements For Different Size And Density Fractions Of Raw Coals

Based on the hypothesis that the levels of sulfur and other toxic tr...

C34060In-Situ Investigation Of Coke Structure Formation Under Stamp Charged Coking Conditions

Stamp charged cokemaking has emerged as an effective technique to im...

Technical Market Support

Mine Site Greenhouse Gas Mitigation

Mitigating greenhouse gas emissions from the production of coal.

Recently Completed Projects

C34066Safe Operation Of Catalytic Reactors For The Oxidation Of VAM Operating Under Abnormal Reaction Conditions

The catalyst Pd/TS-1 has shown excellent activity in oxidising venti...

C28076Selective Absorption Of Methane By Ionic Liquids (SAMIL)

This third and final stage of this project was the culmination of a ...

C29069Low-Cost Catalyst Materials For Effective VAM Catalytic Oxidation

Application of ventilation air methane (VAM) thermal oxidiser requir...

Mine Site Greenhouse Gas Mitigation

Low Emission Coal Use

Step-change technologies aimed at reducing greenhouse gas emissions.

Recently Completed Projects

C17060BGasification Of Australian Coals

Four Australian coals were trialled in the Siemens 5 MWth pilot scale ga...

C17060AOxyfuel Technology For Carbon Capture And Storage Critical Clean Coal Technology - Interim Support

The status of oxy-fuel technology for first-generation plant is indicate...

C18007Review Of Underground Coal Gasification

This report consists of a broad review of underground coal gasification,...

Low Emission Coal Use

Mining And The Community

The relationship between mines and the local community.

Recently Completed Projects

C16027Assessing Housing And Labour Market Impacts Of Mining Developments In Bowen Basin Communities

The focus of this ACARP-funded project has been to identify a number...

C22029Understanding And Managing Cumulative Impacts Of Coal Mining And Other Land Uses In Regions With Diversified Economies

The coal industry operates in the context of competing land-uses that sh...

C23016Approval And Planning Assessment Of Black Coal Mines In NSW And Qld: A Review Of Economic Assessment Techniques

This reports on issues surrounding economic assessment and analysis ...

Mining And The Community

NERDDC

National Energy Research,Development & Demonstration Council (NERDDC) reports - pre 1992.

Recently Completed Projects

1609-C1609Self Heating of Spoil Piles from Open Cut Coal Mines

Self Heating of Spoil Piles from Open Cut Coal Mines

1301-C1301Stress Control Methods for Optimised Development...

Stress Control Methods for Optimised Development and Extraction Operations

0033-C1356Commissioned Report: Australian Thermal Coals...

Commissioned Report: Australian Thermal Coals - An Industry Handbook

NERDDC