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The requirement to increase productivity has been achieved partly through the introduction of larger and more powerful mining and transport equipment.
The requirement to increase productivity has been achieved partly through the introduction of larger and more powerful mining and transport equipment.

Reduction, control of operating costs in the mining, extractive industries

It is incumbent on every extractive operation today to stay productive and deliver quality service, while exploring ways of reducing overheads and downtime. Randall Edson discusses how technologically adaptable solutions and accurate payload measurement technology can significantly reduce operating costs.

Operational, financial and health and safety sustainability are directly linked to ensuring assets are utilised optimally and productively. Removing inefficiencies and addressing productivity improvement begins with accurate and real time measurement throughout plant and process.

For example, the clear and direct visibility and thus control of over or under-loading of materials handling assets, energy optimisation and critical materials life management, together with complete transparency across an organisation’s plant, can be achieved with the use of technologically adaptable solutions.

This paper highlights potential productivity improvement and asset integrity management opportunities. These improvements result in cost per unit produced savings and an enhanced focus on health and safety. In addition, it provides insights into exactly how an organisation operates key assets and ensures the key stakeholders are able to make informed decisions about optimisation for the business as a whole.

Included in this paper are case studies that provide insight into how the operators have achieved significant gains through the use of accurate payload measuring technology.

Volumetric accuracy is a common problem for operations when surveying stockpile output from conveyor belt and crushing plants.
Volumetric accuracy is a common problem for operations when surveying stockpile output from conveyor belt and crushing plants.

Adaptable solutions

This paper provides guidelines and examples of where achievable and measurable reductions in operating costs and increased efficiencies are obtainable for the following:

  • Mobile loading equipment (eg excavators, wheel loaders and track-type loaders).
  • Conveyor systems (conveyor belt and roller/drum bearing life).
  • Transport equipment and infrastructure (mine site, haul trucks, road trucks and haul roads).

The requirement to increase productivity has been achieved partly through the introduction of larger and more powerful mining and transport equipment. Items such as larger haul trucks, front end loaders and excavators, together with increased use of conveyor systems to move product through the mine site process, are being employed. The goal of obtaining optimum payloads and feed rates as well as asset utilisation and stockpile management has been a focus, and often results are mixed.

For example, some of the problems identified include:

  • The increased cost of labour through the need to extend the operational window periods, or the need to re-work the task as a result of lower than planned volume output.
  • Extended operational activities increasing maintenance costs and downtime.
  • Incorrect load management of transport equipment causing increases in fuel usage and maintenance costs, along with inconsistency of volumes being transported.
  • Health, safety and compliance.
  • Volumetric accuracy when surveying stockpile output from conveyor belt and crushing plants.
  • Correct sizing, cycle times and fuel use management for loading equipment.
  • Controlling the actual run time and capacity of crushing and screening plants. Based on issues such as these, a suggestion could be made to focus on adopting a sustainable learning approach to training the workforce, and while this would be beneficial, the provision of accurate and valuable information from the employment of appropriate smart technology and systems far outweighs initial training benefits.

The use of these systems takes the guesswork out of trying to achieve operational efficiencies and productivity in mining operations in load, haul, transport and processing areas through the use of adaptable solutions and accurate payload measuring technology.

Figure 1. “Original” process handling of bulk material.
Figure 1. “Original” process handling of bulk material.

Case study 1: The global miner

The requirement for cost control and reduction for this global miner had a multi-point focus and benefit.

This company moved about 80,000 tonnes per year of product that was an integral part of the process for the production of copper and other high value commodities. The distance from load point (where this product entered the country via shipping lines) to mine site was 500km, and the product was delivered in road train tippers (53.5m in length) with three trailers by multiple contractors.

The original process of moving this material had many risks and opportunities for improvements. Once the vehicles were on the mine site, the drivers would marshal in the unload pad and back each trailer, one by one, into the bay and discharge the product.

Once this was complete, the driver needed to get in the back of the tipper to wash out the body and underframe, to ensure there was no risk of trapped material (from the unloading process) being dropped onto public roads when departing from the mine site. Once the vehicles were washed out, the driver was required to hook the road train back together, ready for the trip back to the load point. Washing out the vehicles caused safety and environmental issues due to the slippery floors in the tipper bodies when wet, and it consumed a significant amount of precious water.

The management of contractor deliveries (material movements) relating to what tonnage and at what time during the shift the load was presented (contractor performance) was also a concern for this company. It was also necessary to understand exactly what onnage of product was on the pad at any one time, to ensure production levels could be met.

Figure 2. “Enhanced” process handling of bulk material via grid system.
Figure 2. “Enhanced” process handling of bulk material via grid system.

The solution

With input from the mine managers/engineers (the key stakeholders), OHS and transportation groups, a drive-over grid, into which product could be discharged, was introduced. This enabled numerous safety benefits and cost reductions.

This grid system had the ability to handle more tonnes per hour than trucks could feed, but the real benefits were in the following:

  • Removal of the requirement to uncouple trailers, as the grid was designed to manage the discharge while still connected in a set-up. The safety benefits gained with this initial phase were outstanding, as the damage caused by reversing trailers in a multiple combination was reduced by 96 per cent in this region.
  • The mitigation of drivers slipping on wet floors, as these trailers now tipped into a grid that did not allow build-up around the back of the trailers and product was allowed to free flow, so the need to wash out was removed. This saved 4.6 million litres of water per year (water is pumped from underground, so not metered usage).
  • With the new system adopted for discharge and receiving, the mining company was able to monitor and manage the in-flow of product into the discharge pad, and all tonnes are now measured into the feeding bins due to the smart technology in place on the belt and delivery systems.
  • This process of automating the collection of material movements has given the mining company the ability to log and monitor the arrival and departure time of all vehicles and reconcile tonnage delivered from each different contractor. The invoicing process for each separate contractor can be initiated (DIFOT* and PIFOT* improved to ~80 per cent year on year [YOY] through additional adoption of automated invoicing and receipting processes) as soon as the load has been completely discharged. This is possible through the adaptable IT solutions built into the software package, which communicates from the grid to the enterprise resource planning (ERP) software. 

*DIFOT – Delivery in full on time. *PIFOT – Payment in full on time.

Incorrect load management of transport and conveyors can cause increases in fuel usage and maintenance costs, along with inconsistency of volumes being transported.
Incorrect load management of transport and conveyors can cause increases in fuel usage and maintenance costs, along with inconsistency of volumes being transported.

Cost savings to operations

The reduction in labour for the drivers was about 11 hours per day. This was achieved by reducing the discharge from three hours per load to a total of 20 minutes per load (78 tonnes per road train), along with a reduction in cycle times, repairs and maintenance for the four scheduled deliveries, presenting a saving of $5060 per day.

A critical value-added benefit of this system was enabling total automation for the collection of information relating to material movements and reconciliation of contractor weigh dockets for the scheduled delivery volumes. Historically, there was a need to chase contractors for the paperwork/delivery dockets to understand when and what time the delivery took place and how much product went through the grid system, which due to the cycle times of the road trains could take hours or even days.

With smart systems in place, the delivery dockets are downloaded and sequenced within minutes of the vehicle leaving the tip site.

The Trimble Loadrite C2850 brings multiple scales onto one display.
The Trimble Loadrite C2850 brings multiple scales onto one display.

The administration team now saves a significant amount of time when invoicing (DIFOT and PIFOT increased to ~85 per cent YOY) and has provided 100 per cent accuracy relating to contractor deliveries.

It also ensures no withheld or late payments are made due to errors or delays of paperwork being handed in by the drivers.

Case study 2: The gypsum miner

An open pit gypsum miner had spent many years working with the same process for raising, screening and managing overburden and finished product stockpiles.

The original process required two 30-tonne haul trucks and excavators to raise, load and transport the ore to a tip over screen/grizzly to remove the remainder of the clay/top soil before reloading it and tipping it into a stockpile ready for crushing.

This process was a difficult and inefficient way of managing the overburden, as the gypsum quantities being screened were unknown. Consistently overloaded haul trucks where being used to transport raised material to the screen at a distance of about 1.5km. The second phase of the process required the re-loading of the gypsum and stockpile and a return journey of the overburden to the pit.

This was a costly exercise, as it required the haul trucks to manage the entire process equating to about 900 to 1000 tonnes of clean, ready to crush rock in a standard 10-hour shift.

Figure 3. “Original” process of extracting gypsum.
Figure 3. “Original” process of extracting gypsum.

In addition to the inefficient haulage process, the fuel consumption was excessive, with the use of a front end loader to re-load all products from under the screen; the haul trucks and an excavator were also required to complete the assigned tasks.

Screen solution

In seeking a solution to this problem, the miner established that if the overburden could be screened, it would produce two products that would assist in cost reductions in the rehabilitation backfill and road maintenance around the site.

Figure 4. “Enhanced” process handling of gypsum.
Figure 4. “Enhanced” process handling of gypsum.

The solution came in the form of a track-mounted crushing plant, into which the raw material could be fed with an excavator. The crushing plant could then screen and crush the required product, which could then be distributed onto the quarry floor without the use of haul trucks.

Cost savings to operations

The efficiencies created in feeding the crusher in pit were:

  • No transporting of waste material, as all the overburden was stockpiled into windrows in the pit.
  • When screening the limestone/clay overburden, it was found that the limestone would produce a good source of roadbase for maintenance on the haul roads around the site, and the clay/loam when screened was 70 per cent better at growing the native grasses in the rehabilitation process.
  • Clean ore could be crushed and stockpiled without having to multi-handle it, and prevented degradation of the finished product.
  • Minimal use of haul trucks with cost savings of about $4000 per day.
  • Maintenance and repairs on haul roads.
  • Maintenance to wheel bearings and brakes on haul trucks and wheel loaders.
  • Labour costs and overtime.
  • Breakdowns due to overloading and overstressing equipment were mitigated/eliminated.
  • Maintenance programs and costs associated with downtime.

Once the crusher was in place and working in the new process, a belt weighing system was fitted to the crusher plant/belts and an on-board scale system in the excavator.

The Trimble Loadrite L2180 wheel loader scales provide an easy way to capture load-out data and help quarry operators make effective decisions with accurate information.
The Trimble Loadrite L2180 wheel loader scales provide an easy way to capture load-out data and help quarry operators make effective decisions with accurate information.

The scales in the excavator provided management with visibility into how many tonnes were being loaded into the crusher each hour/day, and the belt weighing system provided intelligence into if/when the plant was running empty.

The finished gypsum product could then be crushed and stockpiled in-pit, and the excavator was simply required to load the measured tonnes into the crusher. Reductions in costs were measured by:

  • Cycle and loading times for the excavator.
  • Actual feed rates and run times of screening and crushing plants.
  • Real-time stock and inventory management of all screening and crushing plant stockpiles.
  • Improved reporting processes and data management.
  • Safety management through using equipment to manufacturer’s specifications. 

This is where the updated equipment began to demonstrate the true benefits, through the management of the stockpiles.

With the limestone and clay now being separated, the inventory management of these products could be more accurately performed. Further visibility into inventory planning requirements was achieved with the information provided on a daily basis via a belt weigh system.

With additional testing, the limestone (originally a by-product/overburden) could be sold as roadbase material. Contractors/customers could define exact tonnes required and receive product crushed to their required size. This product could then be stockpiled in pit ready for out loading.

With a belt weighing system for stockpile management and on-board scales in the front end loader, the contractors that were inducted to the site could extract requirement on a 24/7 basis. The tonnes could be loaded and accurate information transmitted to corporate ERP ready for invoicing.

The loader scales also saved congestion at the weighbridge on site and removed the need to go back to the pit and adjust for load/vehicle optimisation. The company trucks loading any one of the finished products were now showing reduced turnaround times and increased efficiencies.

Table 1. Return on investment through measurement of outgoing product.
Table 1. Return on investment through measurement of outgoing product.

When looking at the return on investment using technology to measure the outgoing products, a typical scenario such as in Table 1 (above) gives evidence to support the spending for new solutions.

Liability and sustainability

To ensure your workplace is safe and compliant, you must apply risk assessment processes and seek mitigation of any possible corporate liability. Along with this, the rising costs and constraints on your business, the ability to make it sustainable and grow every opportunity to gain a competitive edge must be vigorously considered.

When carefully thinking about the fuel burn and labour savings, and then adding this to the efficiency increases, it is easy to see how using adaptable technology will add to the bottom line and assist with the control and reduction of costs.

While the fleet/equipment is being optimised, and reduction in risks associated with this type of operation is a value-add, it is also important to be able to measure the hourly and daily activities of your business.

In one case study, thanks to the installation of loader scales, company trucks loading any one of the finished products showed reduced turnaround times and increased efficiencies.
In one case study, thanks to the installation of loader scales, company trucks loading any one of the finished products showed reduced turnaround times and increased efficiencies.

To quote the old adage: “If you cannot measure it, you cannot manage it.” This is why using the most accurate payload measuring technology is important.

Improved invoicing timeliness and accuracy, enhanced real time inventory planning and better management of equipment, staff and contractors will augment your bottom line by reducing costs and establish greater control of your business.

This article was originally prepared as a whitepaper for Trimble Loadrite by Randall Edson, G










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Monday, 26 August, 2019 2:58pm
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