David O. DeGagné. Locksley ..... of Queen's. University, and Nils Stewart of Concor Technicrete Mining Services for their important contributions to the Guide.
Mine Backfill, An Operator’s Guide. An interactive CD-ROM for mine operators and engineers.
James F. Archibald Department of Mining Engineering, Queen’s University Kingston, Ontario, K7L 3N6, Canada Ferri Hassani Department of Mining and Metallurgical Engineering, McGill University Montreal, Quebec, H3A 2A7, Canada Jacques Nantel Nantar Engineering, 430 Bernice Drive Kingston, Ontario, K7M 5X4, Canada David O. DeGagné Locksley Innovations Corporation, 12 Glenwood Court Kingston, Ontario, K7M 7G1, Canada
ABSTRACT “Mine Backfill, An Operator’s Guide” is an extension of the electronic book on CD-ROM entitled “Mine Backfill 1998”, which was prepared for the CIM’s (Canadian Institute of Mining, Metallurgy, and Petroleum) centennial celebrations in 1999. Discussions with many operations revealed that there was an industry need for a backfill guide for front-line operator training and as a reference manual for operators and mine engineers. Sponsored by the mining industry and the CIM, “Mine Backfill, An Operator’s Guide” has been developed by the Departments of Mining Engineering at Queen’s University and McGill University to fulfil this need. “Mine Backfill, An Operator’s Guide” is an interactive multimedia package that incorporates high quality colour images, animations, sound, and video with text to review the main backfill methods employed in Canada, including hydraulic/slurry, paste and rock fill. Based on a combination of engineering theory, visits to mines, and discussions with operators, the Guide discusses and reviews key issues, practices, and technology currently in use. The Guide has been designed to be user friendly, includes extensive help features, with operators in mind, and is being distributed on CD-ROM. The Guide is divided into training and reference sections. When in training mode, the operator is guided through a presentation of common mining and backfill practices and technologies so that he/she may become more familiar with different aspects of the backfill process. Beginning with a global perspective, so that the operator becomes aware of the total system, the Guide will then focus on a series of sections covering all aspects of an underground mine backfill system. To ensure that key concepts have been learned, the operator will be tested after each section using a series of multiple choice and true/false questions. When in reference mode, the operator or engineer may browse through the information in a more detailed and independent fashion through a series of interactive menus. The Guide focuses on the following main topics: resources, surface preparation, distribution, stope activities, health and safety, and quality control. Special features included in the Guide are a Buyer’s Guide, a Trouble Shooting Guide, and an interactive glossary of backfill and mining terms. Key words:
mine backfill, slurry, hydraulic, paste, rockfill, interactive, CD-ROM, computer, training, quality control, safety, reference, guide, manual.
INTRODUCTION Backfilling in Canadian mines has been practised for close to 100 years and indications are for the technology to continue at an increased rate in the 21st century. (Nantel, 1998) Fill is one of the most important materials used for limiting caving, subsidence and for supporting pillars and walls. Its use prevents falls and associated air blasts and facilitates recovery of ore. (Coates, 1981) Much of the success of modern underground mining arises from our ability to fill cavities created by mining so as to establish and retain safe working conditions economically. (Thomas et al, 1979) In light of the important role that backfill plays in the Canadian mining industry, a joint co-operative research initiative was established between the Departments of Mining Engineering at Queen's University and at McGill University, under the auspices of the CIM (Canadian Institute of Mining, Metallurgy, and Petroleum), to develop a guide for underground operators, supervisors and mining engineers to review mine slurry, paste, and rock fill technology and practices. Discussions with many mining operations revealed that there was an industry desire for a backfill guide, provided that it focused primarily on front-line operators and supervisor training. A recent survey of 33 Canadian mines revealed that there is a nearly even division between those operations that maintain a dedicated crew (54%) and those that use a rotational crew (46%) responsible for backfilling. The vast majority of mines had some form of training program in place for their backfill operators on surface and underground. The most common form of training for backfill crews was on-the-job training by experienced operators. Organized sessions were ranked second as a form of training. Training is critical to the safe, effective, and economical extraction and processing of ore. In a backfill survey, most mines reported that backfill system failures resulted in no significant losses, however a fatality and cases of infrastructure and equipment losses were also reported. Figure 1 shows a histogram of backfill system failures reported over the past decade. The reasons for such failures can be complex and involve the mining environment and engineering design, as well as operational installation, maintenance, and monitoring. Backfill is often regarded simply as a filler or waste product. While in many operations, where backfill is used for waste disposal or to fill secondary stopes, this may be true, other operations require backfill as part of their overall mining strategy (regional support, cut & fill, primary stope pillars, etc.). For these operations, quality control, and hence training, is crucial.
Pipeline Burst Fill Liquefaction Fill Segregation Pipeline Plug Borehole Plug Pipe Hammering Bulkhead Failure Plugged Sump Pump Failure Exposed Backfill Sloughing Rat Holing Other(s) 0
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1 0 F r e q u e n c y R e p o r t e d
FIGURE 1. Frequency of backfill system failures over the past decade.
1 5
2 0
Additionally, in operations where mine fill is critical to production and development, backfill system failures or delays translate into delays in production. Where poor quality fill may be adopted, consequent ore dilution and loss of structural support may represent considerable economic loss and safety-related problems to mine operations. (Archibald et al, 1993). In the past, mining accidents were often a consequence of poorly designed equipment and inefficient mining systems. As mining equipment and technology has become better engineered, safer and more complex, the frequency of accidents has dramatically decreased. However, the proportion of accidents occurring because of decision errors made by the person or persons involved has increased. (Committee, 1982) Building on experience with 'Mine Backfill 1998' (CIM Special Volume), an electronic reference guide for mine engineers on backfill, it was decided to create the operator's guide as a computer-based training (CBT) module so that the whole range of computer media (text, images, video, animation, and sound) could be utilized to train operators. CONCEPTUALIZATION The project began with the belief that it was not simply enough for an operator to understand what needs to be done, but to justify why something is done, and the safety, quality control and economic repercussions existing throughout the whole operation. While on-site training with qualified and experienced personnel cannot be replaced, the use of a series of uniform training modules allows for the training material to be consistent and the knowledge and experience gained by earlier generations to be pasted along. Additionally, mining concepts are often complicated or remote; or systems are in operation and cannot be shut down for training purposes. The use of advanced media, such as video or animations, combined with process simulations, allow the operator to examine a concept or practice in a new perspective and with no risk to him/herself, others, or property. For example, Figure 1 shows a screenshot from the Guide of a simple-model slurry backfill system simulation. The user can control flow rates and adjust mixing recipes virtually and witness how that affects such factors as pulp density and solids concentration, pipeline pressures, backfill stope stability, and materials costs. Such simulations are not intended to predict values for design purposes, but to model general trends for training purposes.
FIGURE 1. Screenshot of an interactive simulation of slurry backfill system. CBT is a form of functional training, which is a process by which the learner continues until the he/she is able to perform the task or is competent in the skill for which he/she is being trained. It is not time-bound; it is performance-bound. (Osmond and Kelly, 1995) An interactive review quiz placed after each training module ensures that the trainee has a good understanding of the material being reviewed. Such training may have a trainee's test scores stored, for future verification and reference, or be designed to repeat the module until a specified level of performance is achieved.
As variations in operations, backfill systems and corporate specifications exist, it was decided to design a baseline Guide that would provide generally accepted best practices suitable for the widest audience possible. The division of the CD-ROM into two main sections allows mine personnel to proceed directly to a series of training modules, but also allows for a more detailed review of general backfill concepts and theory to be reviewed by mine engineers, supervisors and students. Companies that have sponsored this project have the option to have the general CD reasonably customized to incorporate their corporate specifications and procedures. COMPUTER-BASED TRAINING Horowitz (1997) explains that computer-based training (CBT) involves self-directed, self-paced instruction and nonlinear learning where students can review the material in any order desired. It is technology-based and more convenient than classroom training. Internet-based training (IBT) also has these attributes, and it differs primarily in delivery, with CBT being distributed via CD-ROMs for use on a single computer station and IBT being offered through a corporate intranet or the Internet. A survey of Fortune 1,000 companies found that multimedia-based training accounts for 16% of corporate training and this was expected to reach 35% by the end of 1999. While IBT offers many advantages, such as rapid updating and the option to connect with other students or an online lecture, it was decided to stay with CBT. Although there is definitely an increasing trend in the number of mining operations that have Internet access, the remote nature of mining often means that many operations do not have access to fast and reliable Internet service (INS) providers to connect to the information superhighway. In addition, the creation of on-line classrooms would have been beyond the scope and budget of this initial project. However, with CBT, an operation can use any modern PC computer to train their operators, at each individual's own pace and at a centralized training centre on surface or underground. While IBT will become an increasingly more important medium for training, the technology to bring it onto a mine property is currently limited. As well, CBT and IBT can be combined to produce a hybrid CBT module that can access the Internet to link to current facts and figures such as metal prices, Web pages, or computer files. Many companies world-wide offer CBT services. Locksley Innovations Corporation, based in Kingston Ontario, was used to produce both "Mine Backfill 1998" and "Mine Backfill, An Operator's Guide". The Northern Centre for Advanced Technology Inc. (NORCAT), based in Sudbury Ontario, has been very active in developing many excellent CBT packages and training programs for the mining industry. NORCAT titles currently available include: Workplace Hazardous Materials Information System (WHMIS), Contractor Orientation, Cable Bolting, Ground Control and Support, Scaling, and Physical Hazards (Noise). The largest cost associated with CBT is the initial development of the training content, organization and media. For external development, the cost can range from between $5,000 to $135,000 per instructional hour, with $20,000 to $40,000 being common. The wide cost variation is a function of how elaborate the training is. Special features, such as video and animation, can significantly increase costs. (Horowitz, 1997) However, once the initial design has been developed, CD-ROMs can be created in small batches, as needed, or en masse at very competitive prices per unit and with a faster turn-around than traditional printed textbooks. CBT modules can be updated or new ones added without significant cost increases, relative to the overall project cost, as information or needs warrant. The digital nature of the content makes the medium very malleable and adaptable. Another advantage to CBT is that information can be layered. That is, a general level of information can be provided initially, but through a series of hyperlinks (clickable text or objects), supplemental information can be accessed to provide additional details or clarification, through information on related topics, figures or videos or definitions. One limitation to CBT, however, is that the package must be designed for the lowest common denominator (i.e. for slower computers or lower resolution monitors) in order that as many people as possible can use the software. THE GUIDE After reviewing several authoring packages, it was decided to develop the Guide using Macromedia Inc.'s powerful software engine called Authorware Attain 5.1. While relatively expensive and requiring a significant learning curve to adapt to its icon-based, flow-chart programming structure (see Figure 2), the flexibility and capability of the package makes it a powerful development tool for multimedia interactive development. This software is capable of developing IBT, CBT, or IBT/CBT hybrid applications. Another advantage to Authorware is the licensing agreement that allows developers to distribute their applications without expensive royalties.
FIGURE 2. Screen shot of Macromedia Authorware Attain 5.1 programming interface. Figure 3 shows two screen shots from the Guide. As can be seen in the circular menu (left-hand-side image), from the Main Menu, the Guide is organized into six sections. Sections may consist of a series of sub-sections, or chapters, which themselves may contain a series of pages. A reference primer and a training module make up the primary hemispheres of the Guide. Introduction and help support sections are readily available from the onset to acclimatise users to the Guide. The remaining two sections comprise a trouble shooting guide and a buyer's guide. The left-hand-side of the screen contains a menu bar that remains constantly visible throughout the entire Guide. From this menu, trainees can return to the main menu, access help support, search the CD-ROM by keyword, search the glossary, move between chapters and pages, or exit the Guide. .
FIGURE 3. Main menu of the Guide (left-hand-side) and a page from the reference primer with the glossary activated (right-hand-side). The reference section is designed to act as a backfill primer and includes interactive chapters on the backfill types, uses, mining methods, properties, economics and system components (mixing, distribution and stope activities). The training section is designed in a modular fashion and includes a streamlined backfill primer and reviews of
workplace safety, fill mixing, fill distribution (conveyor and borehole/pipelines), bulkhead construction, stope preparation, fill placement, and trouble shooting. Safety and quality control issues will be strongly emphasised in all modules. The Buyer's Guide will list companies and organizations that provide backfill-related services or equipment. While providing a convenient resource for operators, it also represents another revenue source for the CD-ROM development. The Trouble Shooting Guide is intended to provide a first approximation approach for mine operators and engineers to identify and solve their backfill system problems, based on engineering theory, operational practice and case reviews. It is indexed by component and symptom keyword. CONCLUSIONS As the role and technology involved with mine backfill advances, operator training for both surface and underground personnel becomes increasingly important to maintain a safe, effective and economical mining operation. There is an almost equal split, of those Canadian operations surveyed, between operations using crews that are dedicated and crews that are rotated for backfill operations. Since a failure in the backfill system can result in loss of life, worker injury, equipment and infrastructure damage, and cause significant delays to development and production, it is important that backfill operators, particularly those that are new to backfill or are often rotated, are adequately trained and have an understanding of the importance of their task. Operators depend upon the success of backfilling programs to ensure that mine activities run continuously. (Archibald et al, 1993) CBT, and IBT in the future, represents a significant advantage for the preparation, dissemination and maintenance of engineering, technical and operational guides, handbooks and modules for mining training and education. CBT can be expensive and time consuming to develop and is limited by the slowest users computer system, but it allows for complicated concepts to be communicated in a variety of ways (using interactive text, video, animations, sound and images); for safe simulations of operating principles; and for automatically verifying and recording that a trainee has a good understanding of the material. "Mine Backfill, An Operator's Guide" has been designed to provide a solid baseline tool to be used in conjunction with existing operator training programs. It consists of a series of training modules focusing on workplace safety, backfill mixing, distribution, and stope activities, combined with a reference primer introducing the principles behind backfill technology and practices. On-line help support and a friendly interface has be provided to ensure that the package is user friendly. Additionally, a trouble shooting guide, as a 'rules of thumb' guide for identifying possible system problems and solutions, and a buyer's guide, as a source of backfill related products and services are available. ACKNOWLEDGEMENTS The editors and production team would like to thank the CIM for its support of the Guide. Special thanks must be given to Barrick Gold Corporation, Falconbridge Limited, Battle Mountain Gold Company, Boliden Westmin Resources Limited, and Lafarge Cement Canada for their generous financial support and technical contributions, without which the development of "Mine Backfill, An Operator's Guide" CD-ROM would not have been possible. We would also like to thank Jacques Ouellete of McGill University, Euler De Souza and Ken Wilson of Queen's University, and Nils Stewart of Concor Technicrete Mining Services for their important contributions to the Guide.
REFERENCES ARCHIBALD, J.F., P. LAUSCH, and He, Z.X., 1993. Quality Control Problems Associated with Backfill Use in Mines. CIM Bulletin, 86(972), July-August, pp. 53-57. COATES, D.F., 1981. Rock Mechanics Principles. CANMET, Energy Mines and Resources Canada, Monograph No. 874. COMMITTEE, 1982. Towards Safer Underground Mines. Committee on Underground Coal Mine Safety, National Academy Press, New York, New York. HOROWITZ, A.S., 1997. Net train, net gain? Computerworld, Framingham, Mass., vol. 31 February 3, p. 63+ NANTEL, J.H. 1998. Recent Developments and Trends in Backfill Practices in Canada. Proceedings of the 6th International Symposium on Mining with Backfill, Brisbane, Australia, 14-16 April, Australasian Institute of Mining and Metallurgy, pp. 11-14. OSMOND, F. and R. Kelly, 1995. Changing the Way we Train. CIM Bulletin, 88(986), January, pp. 27-31. THOMAS E.G., J.H., NANTEL, and K.R., NOTELY, 1979. Fill Technology in Underground Metalliferous Mines. International Academic Services Limited, Kingston, Ontario, 293 pages.
