INTRODUCTION OF ROCKBOLT SUPPORT

RMT has unique experience in the introduction of Advanced Technology (AT) rockbolting into coal and other mines worldwide. Projects have been completed in Russia, Eastern Europe, India and Africa. We provide all the consultancy and instrumentation services required for the successful introduction of rock bolting into a new site. This includes the testing and sourcing of suitable local consumables. Comprehensive monitoring schemes can be supplied and installed for safety monitoring and support system design. We also provide training for mine workers and management to assist in the transition to rockbolt support.

MINE LAYOUT

Incorporating geotechnical factors in the design of mine layouts is essential for problem free production. Considerations to be taken into account for the planning of mine layouts include extraction sequence and damaging areas of stress concentration to be identified in advance and their effects minimised. This includes consideration of factors such as horizontal stress effects and interaction with adjacent mine workings. RMT uses underground stress measurement to characterise the in-situ stress regime at a site and numerical modelling to investigate alternative options for the layout of future workings in conjunction with mine management.

PILLAR DESIGN

Correct pillar geometry is essential for maximising mine safety and efficiency. Pillar behaviour and pillar requirements vary depending upon mining conditions and method. For effective design these factors need to be recognised and taken into account. RMT and its staff have extensive experience in research and consulting projects on the stability and design of pillar systems. This includes the design of room and pillar systems, pillar extraction and pillars for longwall workings in coal mines. At key sites we can measure the stress distribution through a pillar. This information is then used in conjunction with rock property testing and numerical modelling of pillar behaviour to verify the design. This is often used in conjunction with computational modelling of tunnel behaviour and reinforcement performance.

COMPUTER MODELLING OF EXCAVATIONS

RMT has extensive experience of the practical application of both 2D and 3D computer modelling to excavation geometry and reinforcement system design in coal measure and stratified rocks. Modelling is routinely used to analyse the influence of variation in parameters such as geology, mine layout and in-situ stresses on excavation behaviour and reinforcement/support performance, including:

• Stress changes due to longwall mining
• Sequential extraction of longwall panels
• Pillar dimensions and stability
• Tunnel stability and support system design

Numerical modelling is used as part of the design process in conjunction with measured data and monitoring to verify design performance. In house facilities and expertise in areas such as coring and rock testing, stress measurement and underground instrumentation are used to quantify the parameters required for model generation and verify the validity of results.

MINE ROADWAY/TUNNEL SUPPORT AND REINFORCEMENT DESIGN

A considerable proportion of RMT's work is concerned with support and reinforcement systems for mine roadways and tunnels. The large lengths of tunnels excavated in mining places a premium on the design of efficient support systems. Designs take into account the intended use of the tunnel and possible stress changes due to mining during its life. RMT has facilities for, and carries out, laboratory testing of the components of support systems to the appropriate recognised standards. Computer modelling is routinely used to characterise roadway conditions, investigate modes of failure or instability and to evaluate alternative support systems. Underground instrumentation is used to monitor strata deformation and the performance of the support system to confirm it's effectiveness and stability.

SUPPORT SAFETY AND RISK ASSESSMENT

A general logic for support system/ground control risk assessment has been developed by RMT. It forms part of a range of risk assessment methods employed by RMT related to general and specific ground control/excavation failure mechanisms. RMT has developed risk assessments for a number of mines. These assessments are site specific due to the complex behaviour of the rock mass surrounding an underground evacuation. However, a consistent approach to developing such a system can be applied by employing a consistent "general logic framework" as a basis for each site. An assessment is made of the important geotechnical and support parameters for a particular site and the "general logic framework" is modified appropriately. Factors which may influence roadway behaviour/stability at any given site include:

• Geology
• In-situ stress and stress change
• Level of support
• Long term effects
• Environment
• Roadway dimensions

All these factors are assessed in conjunction with a full underground visual survey and analysis of all the roadway deformation monitoring available (ie. tell tales, extensometers). This data is then used to identify areas of potential risk. This approach has been proven at a number of sites within the UK, where the risk assessments have been designed to meet the specific conditions at each site. It has been successful in identifying areas at risk or potential risk of failure enabling early remedial reinforcement to be installed to minimise roadway failure which could cause costly repair work and/or delays in lost production.

LONGWALL STRATA CONTROL

RMT has a range of expertise in longwall support design and monitoring:

• Longwall face support performance assessment via data logging of powered support parameters.
• Analysis of longwall caving analysis.
• Powered support capacity specification.

GEOTECHNICAL ASSESSMENT OF QUARRIES

RMT has developed a cost effective approach to hazard and risk assessment of excavations, tips and lagoons. This has been achieved through extensive experience drawn from UK and international mining operations in both hard and soft rock environments

RMT can manage your assessment requirements on a group basis if required.

HARD ROCK TUNNEL SUPPORT DESIGN

Rock Mechanics Technology Ltd., RMT, offer a comprehensive Design Service for tunnel construction from the Geotechnical Assessment of Ground Conditions through to the Support Design and Implementation.

The service can include assistance with:

RAIL TUNNEL SERVICES - Link-up ID Number 21795

As a specialist supplier of rock engineering expertise, RMT offers a unique range of cost effective rail tunnel related geotechnical services and products which are increasingly in demand by Network Rail contractors and engineers including:

To add value to existing examination regimes and tunnel condition investigations RMT's own purpose developed instrument the Acoustic Energy Meter (AEM), can be used for lining integrity testing and mapping. Used for the identification of ring separation and voids in the lining, it has the advantage of being a cost effective survey method which is easy to understand and it gives quantitative readings relating to the physical condition of the lining.

RMT's specialist drilling and coring services bring to the rail industry experience and techniques from the mining industry providing practical and flexible drilling solutions for confined spaces and limited drilling times. Complemented by borehole camera surveying these skills have been used effectively in projects under Network Rail's Tunnel Management Strategies for the identification of tunnel construction shafts.

Clients to date have included Edmund Nuttall Ltd, Birse Rail and AMCO Rail.