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Longwall Improvement at Kestrel Mine
- 1. Longwall Improvement at Kestrel Mine 2010 Longwall Conference, Hunter Valley 2010 Longwall conference slides.pdf Brief personal profile For those of you I have not met my name is John Coughlan and I am the acting General manager of operations at Kestrel mine. I am privileged to be here today to address this conference. Introduction Kestrel mine is located 50km north of Emerald in central Queenslands Bowen basin. The mine was purchased by Rio Tinto in 1999 and is one of 6 mines operated by Rio Tinto Coal Australia (RTCA). The German Creek seam is mined and mix of predominantly coking and thermal coal is produced. We are currently in the construction phase of an extension to the mine, to be known as Kestrel south Kestrel is the only underground coal mine in the RTCA suite of mines. Presently there are 3 development sections, a long wall section, coal clearance to a 3 stage wash plant and a rail load out. We ship approximately 4 million tonnes per year. The facility is self contained and can be illustrated in a typical longwall mine value chain. At Kestrel we are fortunate in that we have 2 available longwall systems each comprising a Bucyrus shearer, 146 x 860t supports, AFC, BSL and monorail and each has a name plate capacity of 2,500 tonnes per hour. These components are of various ages however the supports are original, approaching 20 years in age.
- 2. In 2007 an improvement programme for the Kestrel mine was initiated. The programme concentrated on three broad areas of development, longwall and CHPP. Given this is the longwall conference we will take this opportunity to discuss the longwall improvement. Context In 2007 there were several factors that provided the impetus, or burning platform, to improvement. The mine recently had a new general manager appointed who had some firm views on longwall operations; the longwall should provide the drumbeat for the operation, the longwall should be treated as fixed plant not mobile and finally lean thinking and tools could be applied to better manage process associated with longwall activities. At this time Rio Tinto was undergoing a global change to the way assets are managed and introduced a number of asset management protocols. In the first instance these protocols were to drive a change to planned maintenance and increased reliability as a platform to then initiate further refinement and optimisation of maintenance practices. Increased reliability will then feed into higher operational hours. Rio Tinto was completing the feasibility and seeking approval for funds for the Kestrel Mine Extension. This is an ambitious project utilising a state of the art 375m longwall to underpin a high production low cost mine at Kestrel into the future. Achieving operating parameters such as cut hours and availability assigned to the new system while operating the existing system would underpin confidence in the investment decision. An assessment was carried out with the help of consultants, Deloittes. This assessment identified the broad areas of opportunity available to deliver improvement and provided a framework for the improvement initiatives. Safety First and foremost, to be judged successful any change introduced for improvement has to deliver safety improvement.
- 3. Kestrel continues to set challenging objectives with regard to the health and safety of its employees. We do this as a part of the industry in Queensland and as part of the broader Rio Tinto group. We strive to implement a strategy to develop a culture of trust and transparency driving improved behavioural safety in an environment compliant to regulation and RT HSE standards. Through the period 2007 to now we have directed effort into creating safe people articulating behaviours and setting expectations safe work continued risk assessment and standardisation of work safe equipment improving equipment features to eliminate hazards safe environment using standards, training and contractor management to enable the above Whilst we have improved from 2007 to today, we are yet to make a step change to the next level. We have plateaued. We are performing well within the Queensland underground coal, and opencut, sector. However our challenge is to be regarded as performing well within the Rio Tinto group. We have some distance make up the field where internally some of our RT peers experience incident rates less than 50% those of Kestrel. Structure and organisation Early changes made at an organisational level centred on creating 24 hours per day of opportunity to cut coal. This was not available to the longwall operations. Split start times were created to create access to sufficient skilled labour operator, maintenance and statutory to supplement operations through a shift change. The roster makes use of 12.5 hour shifts so nominal shift starts at 6:00 and 7:30 on day and night shift were implemented to maintain people at the face for a period at either end of day and night shift, while other crew members travelled either in or out of the panel. A hot handover at the face provides face activity continuity and is self-sustaining as an incumbent crew cannot leave until the replacement crew arrives.
- 4. Support crew composition was adjusted to provide the skills and people through this window period. This meant that when required the support personnel could be at the face cutting and when not they could be performing other support tasks. Longwall planned stoppages were organised around a single time in the week to conduct maintenance and support activities for the longwall and clearance system. This day is developed around pulling up early at a predetermined time, executing the tasks in the day to a locked in plan and then cutting at least one shear at 5:00pm to set up for the following shift. Planning and execution of the maintenance component for this day follows the discipline established by the work management process. The rebuild process for the alternative longwall system had a full and comprehensive review. The emphasis of the rebuild changed from fix to overhaul and project management discipline is applied through the scoping, implementation and finalisation of each rebuild step. Much of the scoping has been conducted through RAMBO and defect elimination methods, highlighting tasks previously not undertaken eg replacement of valve gear and the removal of all the redundant system to be worked on at the surface. Reliability The asset management protocols mandated by Rio Tinto have been in place since 2007 with their intent to increase reliability. These protocols provide discipline to the: management of maintenance work identify, plan, schedule, implement, complete, analyse reduction of contamination for example improving support pressures o improving the quality of water to 7 micron to protect valve gear o emulsion plant to prepare emulsion and deliver to pump at a pre-determined quality elimination of defects for example reduced DA ram failure by increasing rod diameter from 100 to 120mm operation for reliability for example analysing the best cut sequence to 60:40
- 5. maintenance tactics determining task frequency and opportunity to carry out work in the cutting cycle The approach to reliability in our longwall operations was further promoted through the attendance of operations and maintenance leaders at a Ron Moore reliability workshop where the message was clear reliability is not a maintenance accountability. This initiated a site longwall reliability workshop involving operations, electrical and mechanical personnel facilitated by an asset management professional from RTCA. A process where barriers were identified, prioritised and turned into objectives derived a series of subsequent actions to be implemented. These actions comprised process, administrative, logistics, repair and standardising tasks. A particular effort has been put into management of maintenance work through the work management process. This is the RT asset management protocol that required a discipline to be installed. The Kestrel outcomes in this process are measured and benchmarked with all RT operations in what are called the global metrics. This has created a significant step for maintenance work to move away from a reactive domain to a planned domain. Cutting practice A study was carried out on the cutting modes to determine the extent of discretion being applied over the parameters on a crew basis and through observation of load ratings how this variation placed stress on the operating system. This study determined a 60:40 push to maingate parameter and change management was used to install this practice across the 4 operating crews. The key to the change management was the use of a trial across the crews of the various parameter sets; 80:20, 70:30 and 60:40. Each parameter was used by all crews for a week and data was obtained during this time. This meant each crew had first hand experience in each parameter set, could observe what was taking place and understand the assessment of each technique. The study concluded the 60:40, while not giving the best instantaneous productivity as the best cutting pattern with regards to safety of the operators, reliability of equipment, distribution of load and productivity of the mine.
- 6. Kestrel took a more energetic approach to automated cutting during this time. There was some automation facility available in the form of an inclinometer system and Bucyrus software. However there was little confidence in the facility and take up of it had been unenthusiastic. Moves to change the perception of automation and capitalise on the benefits consisted of 2 strategies; (i) upgrade the technology to a reliable and accurate system and (ii) educate and train the operators to sufficiently grow their confidence in the use and benefits of automation. Technological changes included an upgrade from the inclinometer to an IMAR system with associated software adjustments. At this time the mine also implemented a broad ranging SCADA change through CITECT capability. Now real time information was more readily accessible and the capacity to monitor automation, and other, activities was improved from the previous macro-view capability. Further assistance in monitoring is now available through the provision of push reports detailing activities and time. Several tactics were used to educate and train operators. A champion for the technology was identified and introduced a move prompted from a previous paper presented at this conference. The champion has been rotating though the crews on 2 month blocks. The role of the champion has been to teach the technology, provide feedback and confidence that the technology works, educate the operators in the broader quality aspects of cutting using the roof as the target, speed for operations, arms for quality in a manner that was more what to do not how to do it. This involvement with the crews was made easier when the operation scaled back from 4 operating crew to 2 in response to the GFC in 2009. The concentrated effort on these 2 crews, and that they always returned to their workplace, meant they were proficient when the operation went back to 4 crews. The effort then went into the other 2 crews. The Bucyrus model was brought to site. Operators were able to experience automation usage in a simulated environment.
- 7. Now 18 months on there is widespread acceptance of the automation. We are now in the process of rotating a skilled trainer across all the crews to standardise the how to do it aspect. Our push reporting now shows that we have 80% of the cutting being conducted in the automation mode. Process improvement A number of longwall processes were addressed through improvement projects. Lean was introduced to Kestrel at this time and after visits to RTA to look at how it can work, application of 5s, visual workplace and standardised work became widespread in the operation. Information boards were designed for the longwall group and these became the focus area for crew briefings and progress tracking, both performance against plan and issues resolution. Waste elimination projects such as the overhaul trolley were undertaken a trolley that houses tools, parts and enables isolation of a single chock. We introduced a CITECT system improving the access to realtime data and feedback across operational crews. Reports and system status are immediately available at the maingate and transformer computers. These reports are available across the network. In addition we are developing the capability of LVA beyond simply a geotech aid. The retraction process was reviewed with a view to QCO reduce the time from last shear to first shear. While the sequencing of tasks was analysed to determine the best allocation and use of labour, capital was invested in the form of a second transformer and pump station. This has enabled a leap frog approach to be applied and time savings of up to 8 hours have been achieved. The commissioning of each installed longwall system post install has been defined as a process. This starts with a dry phase where there is a run through from power off to power on with no picks in coal. A disciplined process is then applied to the wet commissioning as increased numbers of shears are achieved as prescribed checks are completed. The key to this stage is that the checks take precedence over the shears, containing the urge to just get going and underpin reliability later in the block.
- 8. Along the way In January 2008 we had the floods in Emerald. While this did not directly endanger the mine, the mine was indirectly affected by cut roads preventing workforce access and water quality. Access was maintained to the mine using chartered aircraft and a rotation of mine critical staff and officials. This kept the mine open, ensured that any critical issues could be managed and set a platform for remobilisation once the flood situation eased. However our real test came when the longwall was initiated. At this time we were commissioning the longwall system in the 305 block. The existing filtration of raw water could not handle the changed water quality, with higher levels of sedimentation, leading to continued valve failure in the chocks. In the short term the mine resolved this using an IMT approach - coupled with some constraint theory (throw everything at the bottleneck eg charter a plane to bring a full changeout of valves from and OEM) - by changing out most of the valves in the system, installing a potable water supply and then proceeding with the purchase and installation of a bulk emulsion plant (we may have been a bit behind the field on this one) In 2009 the coking coal market depressed rapidly with the global financial crisis. The Kestrel response to this was to throttle the mine output in direct proportion to confirmation of sales. In the longwall a cutting programme was developed using 2 crews out of 4, the operating principle being that the longwall would run hard for a period then stop rather than advance continually at a slower rate. The improved reliability and chock performance enabled this strategy. Labour not required in the longwall through the non-cut periods was reallocated, essentially replacing contract labour. Personnel were deployed to development sections, CHPP and the chock overhaul project. Full manning resumed later in the year most people returned.
- 9. Where are we now H1 2010 has seen the manifestation of improvement in the operation and changeover of the longwalls. The improvement can be seen in the ytd achievements; cutting hours achieved per week days per 1st 100 meters cut in a block annual expected metres retreat annual expected ROM tonnes annual expected saleable tonnes There have been no significant roof events since the support system improvements were made. The future While we have made these changes to date through the efforts of a very dedicated team, there remain a number of challenges to contend with. The remaining blocks in the 300 series show an increase in cross grade as these blocks progress up dip. This is increasing wear and stress on the drives, chains, racks and trapping shoes. As we progress up dip we mine in closer proximity to an overlying aquifer. There is a likelihood of water ingress into the workings so drainage and pumping mitigation factors are being implemented. We continue on our automation journey. We are going to install, commission and bring up to steady state operations a new 375m unit at Kestrel South.