Operational efficiencies at mines can be obtained in any number of ways, but rarely does there come an opportunity to save not just hours, but days, in a given year thanks to a relatively small change in operational procedure. The advantages are, of course, multiplied when that efficiency also equates to a significant cost savings for the mine.
A complex in the oil sands region of Alberta, Canada, recently realized significant improvements by automating its truck refueling procedures for its ultra-class fleet of 34 Caterpillar 797s, 13 Cat 793s and 14 Komatsu 930Es with the help of Wenco and its Fuel Dispatch system.
Fuel levels prior to the implementation of Wenco’s Fuel Dispatch.
Inside the system’s scheduler.
Wenco and Fuel Dispatch
Wenco, a subsidiary of Hitachi Construction Machinery and headquartered in Richmond, British Columbia, Canada, first announced its Dynamic Fuel Dispatch system for fuel efficiencies in mid-2014 to a receptive audience that was seeking both conventional and unconventional ways to save time, money and resources.
Specifically, Fuel Dispatch assesses current fuel levels in an active haul truck, then calculates each machine’s remaining fuel time using an algorithm that includes data from the unit’s model, status, and its uphill and downhill travel.
Vehicles with OEM fuel monitors, such as the Caterpillar 797s, have the option of polling these systems to determine the fuel hours remaining, and Wenco Fuel Dispatch also has the ability to integrate with OmniComm fuel sensors as well for sites that utilize them.
Once the system determines the unit’s remaining fuel hours, it checks results against the system’s preconfigured thresholds for fuel dispatching; two figures are maintained, a suggested threshold and a critical threshold.
Fuel Dispatch, once at the suggested level, creates an event that dispatchers can see in the Wenco mine eventing system Event Monitor, alerting that there is a truck that is a candidate for fueling; additionally, the next time that truck exits a dump location, it can receive a dispatch assignment for refueling, and once at critical levels, an immediate alert will signal with the assignment of the machine to a refueling station as soon as it exits its dump location.
Fuel Dispatch, now with a candidate on log, will search the mine for available fuel locations that are preconfigured into the system via Wenco’s Fleet Control.
“Dispatchers use this application to assign new fuel locations — either stationary fuel bays or specific locations for a mobile fuel trucks,” Wenco dispatch team leader Andrea Blazenko said, adding that the oil sands regional client used only stationary fuel bays.
￼Wenco notes the fuel levels at fuel times after Fuel Dispatch was implemented.
Smaller Changes Create Big Impacts
It goes without saying that fuel is expensive — and any surface mine operator will quickly admit that refueling operations is a significant cost on its daily balance sheet.
“It’s not just the fuel being a large expense, but an inefficient fueling operation can lead to a decrease in availability of important mining equipment,” said Blazenko. “[This] can significantly alter a mine’s overall production.”
Mines that do not possess an efficient refueling operation are spending much more money and time than they need to, primarily due to removal of equipment from production to refuel too often (whether or not that refueling is done on a set time schedule) and possibly even refueling without knowing the current fuel levels of the machine — particularly with machines that do not possess an OEM-installed sensor. Additionally, unnecessary man-hours are spent fueling equipment when it’s not needed.
￼A comparison of refueling schedules by model number and time period studied.
A Case Study in Efficiency
A top producer in Alberta’s oil sands region began using Wenco’s automated fuel dispatching service in January to its total of 61 haul trucks at a truck and shovel mining operation. The Cats in the study had OEM-installed fuel sensors, but the 14 Komatsu 930Es did not have one installed.
The site first began examining its historical fueling data in November 2014, at which time it noted some concerning results to Wenco. Management reported that, during the previous year, its Caterpillar 797 haulers were averaging 12.6 hours between fueling sessions, and that its smaller Komatsu 930E trucks, those without the OEM fuel monitors, averaged just nine or 10 hours between fuel sessions — an “unacceptable result,” according to Wenco, which noted that no fuel efficiency system was used prior to the two parties collaborating on this project.
“Rather, dispatchers used data drawn from vehicles’ OEM systems or a standard heuristic model to determine appropriate points at which to send trucks for fuel,” Blazenko said, noting that the 797s were sent for fueling based on the remaining fuel hours indicated by their VIMS systems and the Komatsus were filled for every shift regardless of fuel level.
“Operators would perform fuel runs independently of a dispatcher assignment when concerned about their remaining fuel levels [and] communication of OEM fuel levels weren’t sent to fueling operations with any consistency,” Blazenko said. “Without a fuel efficiency system, most site personnel were unable to know the remaining fuel hours with accuracy and, instead, erred on the side of caution.”
The implementation of Fuel Dispatch carried a myriad of benefits for the site: a reduction in the number of operational interruptions, having control over unnecessary refueling, and keeping wait times at fuel locations to a minimum. Within the algorithm, just as it was designed, the system considered travel time for the trucks from their current location to the fuel bay, the queue/wait time at the fueling locations and the amount of time that would be needed to refuel the machine. Each was specifically input into the system based on equipment model.
In the case of the study operation, the fueling site closes its bays for two hours, twice a day. That information was incorporated into the Wenco system, allowing all of the trucks’ thresholds to remain in order, which prevented trucks from exhausting all fuel while the bay was closed.
In the initial setup of Fuel Dispatch, the system was configured with a suggested fuel threshold of five hours and a critical fuel threshold of three hours. That has since been changed by dispatchers to lower thresholds; suggested is now 3.5 hours and critical is two hours.
“The operation actually projects times of 2.5 hours suggested and 1.5 critical if it were to keep its fuel locations open 24 hours a day,” Blazenko said. “Given these thresholds, trucks still receive fuel dispatches with 15% to 18% of their fuel tanks remaining — about 1,000 liters for the Caterpillar 797s, more than enough to perform several haul cycles.”
Success in Numbers
Even with the restrictions noted above, Wenco said the producer was able to extend the time between fueling sessions to 16 hours; in other words, for every three runs for fuel, they have gained an additional free fueling session.
At the refueling rate of 16.5 hours, the site’s haul trucks now are spending approximately 221 hours annually fueling (based on 25 minutes for each average fueling session), versus previous figures, where the Caterpillar fleet spent approximately 279 hours a year fueling. That equates to a total time savings per truck of 58 hours, or about 2.5 days of production per truck, per year.
The Komatsu 930Es, which again did not run with OEM fuel sensors, gained even more uptime, Wenco said. They went from refueling every shift to an estimated increase of 164 hours per year, or almost a week per truck.
“The results from the January trial of Wenco Fuel Dispatch at the oil sands producer prompted managers to purchase a full license for the system within three days of configuration,” Blazenko said. “Since then, the site has continued to use the system to great effect, producing a quantifiable return on investment by gaining over three additional net operating hours per fueling session.”
The Alberta operation was able to increase hours between refueling across all of its fleet models.
The Wenco group noted that the study the two undertook has yielded additional benefits for the operation. First, the system gave management accurate data on its refueling times and travel times based on status changes, and those officials have been able to see streamlined metrics and create new models for even further improvements.
Additionally, the operator has performed further studies to determine whether they should be changing their fuel bay locations to be closer to their active mining areas as well as other methods to reduce time loss from personnel delays.
“Automated fuel dispatching has strong potential to streamline the fueling cycle and reduce the time haul trucks spend out of production,” the company said, noting that the case study site has exemplified that.
“In total, automated fuel dispatching as provided by the Wenco Fuel Dispatch system has provided [it] with weeks of saved production time and has demonstrated that fueling inefficiency can be controlled and optimized at mine sites to generate stronger returns.”
This article is adapted from a presentation by Wenco’s Brad Stilley at Haulage & Loading 2015, held May 17-20 in Phoenix, Arizona. The original white paper was written and compiled by Wenco’s Devon Wells.