Applying business process improvement measures has played an important role in Sandvik’s Canning Vale Productivity Centre in Perth successfully completing a highly complex rebuild of a DL420-10C production drill for gold producer La Mancha Resources Australia.
The rig, LH002, has been working at La Mancha’s Frogs Leg mine near Kalgoorlie, since October 2009, as the mine’s front line production drill in a long-hole stoping capacity.
Fitted with Sandvik ST58 drilling consumables, it predominantly bores 89 mm up-holes to a depth of ±25 meters. At times, it is also required for reaming to 200 mm in rock and 252 mm in paste.
Since its initial delivery – operating around the clock – LH002 had logged approximately 9000 percussion hours, 14,000 power pack hours and 1000 engine hours.
According to Wayne Stewart, Maintenance Manager at Frogs Leg, over its life the rig’s drill module had been overhauled several times, but little work had been carried out on the carrier.
“We were encountering increased issues with hydraulics, hosing and electrical downtime which was affecting its productivity and increasing the unit cost,” he said.
Cost effective option
To overcome these issues, Sandvik proposed a rebuild option as a cost-effective alternative to purchasing a new machine, bringing LH002 back to as-new condition and complying with Sandvik OEM specifications.
“We were looking for the most economical solution to fit our long-term mine plans,” Stewart said.
“The main alternatives we considered were to stay ‘as is’, do a minor component overhaul, major overhaul or replacement.
“At roughly 60% of new price, the major overhaul was considered the most effective option available to us,” he said.
“Outside of increasing reliability and reducing unit cost, rebuilding supported other key criteria such as returning the drill functionality, electrics and hydraulics to original specifications and upgrading unsupported components.
“Negotiating the rebuild between La Mancha and Sandvik was quite a long process,” Stewart said.
“Becoming comfortable that both parties had an aligned view of outcomes and expectations was an important aspect of the rebuild process, and one which Sandvik supported with capability information, historic data and just many hours turning expectation into specification.”
Brett Kervin, Sandvik’s Business Improvement Service Manager at Canning Vale, said that a machine rebuild of this nature was “right up there” in terms of complexity, so it was of the utmost importance that its Canning Vale Productivity Centre be set up to handle the project’s needs.
To ensure this, the Productivity Centre implemented a number of business process improvement measures, applying Lean methodology principles and procedures to optimise the rebuild process.
“We took the opportunity to adjust the physical layout of our workshop in preparation for this rebuild – and subsequent rebuilds in the future,” said Kervin.
“An important message from our Lean methodology is that a poorly organised workplace leaves the potential for unsafe practices, unnecessary rework and longer repair cycle times, which can have a significant impact on costs and delivery schedules.
“The ability to remain flexible is also a key component of repair work when dealing with the range and complexity of hard rock mining equipment our Perth Productivity Centre is required to handle.”
Kervin said that while there is considerable variation in most equipment rebuilds, there were also opportunities to standardise the mandatory and non-negotiable elements of the rebuild processes, as reflected in the customer’s requirements.
“Through applying Lean thinking and concepts, coupled with workshop team brainstorming sessions, we were not only able to break the machine down into its usual high-level components, but we could also optimise our work breakdown structure and ensure the efficient and timely delivery of parts to the job.”
Dealing with the unexpected
These processes also ensured that the rebuild program – which took place between March and June 2015 – was able to deal with any unexpected issues quickly and effectively as they occurred.
“We had a few surprises along the way, but we were able to deal with these immediately through our implementation of a robust root cause analysis (RCA) process and the clear benefits of Sandvik’s OEM supply chain,” said Kervin.
“One example of a surprise we encountered was unforeseen damage found on the drill’s inner boom tube.
“This part of the boom assembly is effectively hidden, and during the quoting process was not factored in.
“The lead time given to supply a replacement item meant we risked missing our delivery target, which caused a great deal of concern.
“However, upon contacting Sandvik’s Australian product support manager Harold Jonker, we were able to quickly locate a complete boom assembly that contained the inner boom tube we needed,” he said.
“Our parts division promptly shipped the assembly to us so we could proceed with the rebuild without losing any time.
“That was a fantastic example of how Sandvik’s Service, Parts and Product Support networks can leverage off each other in order to resolve problems – solutions that are not available to third-party providers,” said Kervin.
Visual Management application
Another integral part of Lean methodology is a process known as Visual Management (VM), which Sandvik continually strives to improve throughout its workshop operations.
“The more effective our VM processes, the less time we wasted through talking in meetings,” said Kervin.
“We were able to apply VM very successfully to this rebuild to improve safety, work quality and efficiency, and workflows.”
Some key ways in which VM helped Sandvik’s Canning Vale technicians during this rebuild process included:
- The ability to identify unsafe or abnormal conditions, ensuring all work was carried out safely
- The ability to apply the correct standards of repairs efficiently and according to plan
- Prioritising work to ensure the workshop team followed the critical repair path, eliminating the risk of waiting and ensuring optimum work flow
- Ensuring the entire team knew the targets and tracking of progress through performance dialogues
- Ensuring a robust process of communication and feedback to all stakeholders
- An in-process control system, using “quality tollgates”, which has a direct bearing on the RCA (root cause analysis) process through early detection of potential defects or rework; this is a critical aspect of the rebuild with the aim of eliminating as many teething issues as possible through to the end-of-rebuild testing.
“Our RCA process forms an important input of our post-rebuild review,” said Kervin.
“This, combined with our ongoing process improvement reviews during our rebuild, allows us to identify further improvements we can make to the parts supply chain and delivery of parts at a sub-job level.
“These allow us to find greater value for our customers, which will have a positive outcome in terms of both time and cost savings for future rebuild projects we carry out,” he said.
Frogs Leg Maintenance Manager Wayne Stewart said that once the project started, communications were “regular and transparent”.
“Weekly progress reports kept us abreast of any upcoming issues and risks, plus Sandvik’s plans to deal with them,” said Stewart.
“We carried out two inspections: one at roughly the rebuild mid point and another two weeks prior to delivery.
“Importantly the rebuild was completed on time and budget.
“And given the comprehensive scope of the overhaul, the overall quality of the machine was excellent,” he said.
“There were some issues encountered while commissioning; however, these were dealt with in a timely manner.”
Stewart said that while it was still early days, and performance over time would be the ultimate decider, to date the rebuilt machine had performed to expectation.
“The commissioning support from Sandvik was equal to that which would be expected with a new machine – so great service.
“And follow up on issues has been timely and forthcoming,” he said.
SIDEBAR: La Mancha’s DL420-10C rebuild process
The rebuild process covered the following:
- Complete strip, sandblast, and NDT (non-destructive testing) crack testing and repair (followed by final NDT at the end of the process)
- All articulation and drilling module bores returned to factory specifications
- Completely new drivetrain, covering engine, transmission, drivelines and axle assemblies
- Complete hydraulic lines “re-hose” back to factory specifications
- Complete drilling and 24 volt rewire, including operator consoles, again back to factory specifications
- Upgraded drilling control modules to provide improved reliability and functionality
- Extensive fabrication repairs to bring the rig back to full OEM specifications.