You can read more about this data type in Part I. 

Another benefit of a digital replica is that it allows a graphical construction of an ‘inching sequence’ —the precisely planned order in which bolts and liners are removed from the mill. This process is often constrained by access limitations and geometrical differences. The inching sequence can be difficult to predict in advance, and small changes can have a significant impact on the total reline time. 

When plans are being developed for future greenfield sites, mill operators typically want to be able to model different scenarios, to assist with making plant design trade-off decisions. Since the mill doesn’t exist yet, the model is built through a discovery process with the Customer, and their mill and liner manufacturers. 

If these details are not available, RME is able to propose a range of different common liner arrangements as part of the trade-off study*. RME has a large industry database of actual reline performance data for similar real-world mill scenarios, which is used to validate model constructions. 

In the case of an already operational site, RME would usually attend site to film the reline and collect the data required to construct the model.  

*Note that when RME proposes liner designs for reline simulation purposes, we only consider the number of liners for each type, and associated fasteners that are required, and are not considering the actual liner grinding geometry and wear patterns that vary between sites. These other factors may have a design feedback loop into the number of pieces for an optimised liner design. The best approach for accurate reline modelling is achieved through collaboration: when a liner OEM provides liner design(s) specific to the project as an input into the construction of the MRD model.  

Filming the real-world mill reline 

To create a highly accurate digital twin for existing mills, RME’s MRD engineers travel to site during a shutdown to film a real-world reline operation. This involves placing customised video cameras inside and around the mill, to capture every minute of the operation. The video footage is later used to develop site-specific datasets with statistical distributions of the time taken for each activity. These datasets then become inputs to the digital replica.  

By combining expert site observations with captured filmed data, MRD can identify and produce quantified site-specific improvement recommendations using the digital replica. 

Global industry performance benchmarking 

After capturing actual reline time data, RME can perform an industry benchmarking exercise of relining performance using our extensive datasets. This gives mill operators a view of their current performance relative to similar operations worldwide. Benchmarking is done by comparing overall reline times achieved as well as individual activity times.  

Benchmarking has three benefits. First, it gives Customers an external reference point—helping them understand how they compare to the broader industry and offering some initial clues about where to look for potential improvements. Second, it helps keep the modelling work grounded in real-world conditions. And third, by showcasing illustrative examples, it encourages constructive discussions that challenge the status quo (i.e. 'this is the way things have always been done'), paving the way for relining optimisations. 

Trust and validation

The initial, full simulation that MRD runs is what’s called the ‘validation reline’. This is where a scenario is constructed in the model that exactly replicates what has occurred in real life at site. This is built from the data captured during the filming and study of the reline, and includes mill details, liners, relining equipment, crew size, reline work rates, and delays from external factors. 

Establishing baseline performance  

Now that we have confirmed the model is accurate, the next step is to produce the ‘reference reline(s)’. The reference reline represents the site’s typical baseline reline performance and is built to match the reline schedule over the next 1-3 years. In this way, the model predicts what the site can expect their annualised reline performance to be, should nothing change. This is often reported as a total time spent relining in hours per annum, or the percentage of lost mill availability per annum.  

The baseline model can also be used to quantify how many hours the reline crew will be exposed to safety hazards, based on the duration of the reline and the number of workers required in each zone of the mill. This is often reported as person-hours of risk exposure per annum. 

Once the baseline models are completed, it is then possible to make changes to the models that consider different ‘what if’ scenarios.  

Asking site-specific ‘what ifs’ 

The wide range of questions we can ask were highlighted in Part II of this series. For example, “How much time—and how many crew risk exposure hours—could we save by automating the operation of THUNDERBOLT Hammers using SKYPORT or SKYWAY suspension systems?” 

In the case of a filmed study for an operational site, we can also examine the relining processes and methods as levers for improving mill availability. This may involve optimising the liner supply system, reline crew allocation, relining sequence and more. It also could include identifying recurring sources of delays (e.g. mill drive issues) and quantifying how much time could be saved by addressing those issues through targeted investment.

You can also watch an animation of an MRD reline operation here.

When filming the reline isn’t possible. 

There will be times when filming the reline isn’t possible—for example, at a planned greenfield site. MRD has a solution for this too. Our Desktop MRD Studies will use information from drawings, project data, and similar project experiences to make reasonable assumptions. We also draw on our extensive relining database, which includes data from similar mine sites, locations, mills, ores, and liner types. From here, we calibrate the desktop models up or down to produce the reference reline and run the ‘what if’ simulations. 

Of course, MRD Desktop studies are not as accurate as MRD filmed studies, because we can’t be as specific with things like the exact crew experience and relining speed. However, for greenfield projects, a Desktop MRD simulation is the most accurate way to predict reline times and generate data for informed trade-off decisions. Simulations will compare mill availability against various plant layout and capital investment options, allowing for optimised decision-making from the outset. 

What can an MRD study do for your site? 

Since the program’s release, MRD has helped hundreds of mill operators make better and more informed decisions about maintenance planning and mill availability. Our methodology provides clear line of sight into the complex process of mill relining and serves as a trusted, data-driven independent assessment of plant designs, relining processes, equipment, and crew performance. Moreover, it helps operators build a solid business case to justify CAPEX and OPEX budget requests and investments— because we can clearly demonstrate, with a solid amount of certainty, the economic impacts on annual mill availability and reline safety. 

Curious about the impact of MILL RELINE DIRECTOR (MRD)? 

RME has published a whitepaper detailing the results of a non-filmed MRD study that quantifies the knock-in effect of THUNDERBOLT MAGNUM Recoilless Hammer technology on reline duration and mill availability. Simulations were conducted across a range of mill scenarios and relining conditions representative of global industry practice. The study revealed annualised reline time reductions of up to 74.7 hours with optimal hammer configuration. 

Download the whitepaper to explore the findings. 

As John Russell—RME’s Founder—puts it: 

Thank you for following our three-part article series on MILL RELINE DIRECTOR. If you have questions about MRD simulations and site-specific studies, the RME Mill Relining System and RME’s Mill Relining Optimisation Program, please reach out to our Applications Engineering team via your nearest Regional Support Centre or email rme@rmeGlobal.com. 

To get a sense of where your site compares against industry norms, explore the new RME Mill Relining Benchmarking Scorecard. This intuitive, web-based tool provides an external reference point—indicating how your operation compares to similar mills in RME’s global industry database, and where there may be opportunities to improve safety and performance. To learn more about the Scorecard’s capabilities and its role, read Behind the Benchmark: Fireside Chat with RME Applications Engineering Team.