Methodology for Evaluating the Cost of Safety Compromises at an Open-Pit Coal Mine

In open-pit mining operations, the high dynamics of technological processes often push site supervisors toward operational compromises. Haul roads change their configuration every week, and in pursuit of coal extraction rates, there is a temptation to temporarily mine a section with a narrowed roadway or postpone the isolation of a small area of spontaneous rock heating. However, attempting to save time on workplace preparation results in hidden production losses: equipment idles in queues, the hourly productivity of excavators drops, and the concentration of hazards increases. Ilya Musatov, Deputy Director for Occupational Safety and Production Control at SUEK-Khakassia, uses the example of the Chernogorsky open-pit mine to examine in detail a methodology for translating such compromises into the language of corporate economics.

How Safety Compromises Turn into Operational Downtime

At an open-pit coal mine, it is important to distinguish between an isolated violation and a hazardous operational situation (HOS). If a deviation in road or work pad parameters cannot be eliminated immediately without pulling bulldozers off waste dumps and making an unplanned redeployment of auxiliary equipment, the crew is forced to work under conditions of elevated risk for a certain period. Attempting to compensate for design deviations with organizational measures only creates an illusion of a solution and directly hits output:

• Narrowing of haul roads. With a design roadway width of 27.5 meters for BelAZ-75306 haul trucks, the appearance of a 150-meter-long bottleneck is often addressed simply by installing priority signs and briefing drivers. In practice, a loaded haul truck moving uphill has the right of way, while empty trucks line up in a queue instead of moving to the loading area. Since several excavator fleets use the same transport artery simultaneously, the total downtime of three excavators reaches 155–245 minutes per shift.
• Delayed isolation of rock heating zones. If a heating zone is not smothered with rock mass at an early stage, it expands and fills the mining face with thick smoke. Haul truck drivers are forced to operate in minimal visibility, which reduces haulage speed and turns a localized issue into months of additional work.
• Unmarked power cables on excavator pads. Due to the structural offset of the BelAZ cab to the left, the driver has an extensive blind spot on the right side. A cable that is hard to see in the dark is highly likely to be damaged by a haul truck, leading to four hours of excavator downtime and a shortfall of about 2,000 tons of coal delivered to the processing plant.

Methodology for Calculating the Cost of HOS: Translating Risk Scores into Rubles

A traditional five-point matrix for assessing likelihood and severity helps the occupational safety department rank threats, but for mining site supervisors, an abstract risk score often remains an intangible figure against the backdrop of strict production targets. To change production managers' attitude toward deviations from design parameters, the Chernogorsky open-pit mine introduced a calculation of lost revenue resulting from operating under HOS conditions.

The methodology is based on comparing the direct costs of eliminating a non-conformity with the financial losses from mining and haulage equipment downtime. The downtime of each excavator per shift is scaled to a monthly forecast. For machines operating on overburden benches (for example, Komatsu PC4000 and PC2000), the unmoved volume of waste rock is converted into a finished product equivalent using the stripping ratio, and then added to the losses of coal-mining excavators.

The calculations demonstrate clear arithmetic: continuing to operate a single narrowed road section costs the open-pit mine nearly 65 million rubles in lost revenue per month across three excavators (12.3 million and 10.6 million rubles at overburden complexes and 42 million rubles in coal extraction). Meanwhile, the one-time cost of bringing this same road section up to design parameters is 4.5 million rubles and requires only half a shift of equipment operation. When site supervisors began recording lost revenue in monthly HOS registers, it turned out that the total potential losses from operating with such compromises over several months exceeded 192 million rubles.

Integrating the HOS Register into the Operational Management System

Introducing financial evaluation became part of a comprehensive overhaul of risk management at the enterprise. Instead of formally maintaining spreadsheets, managing hazardous operational situations was integrated into the operational management system (OMS) and the supervisor's standard of work:

• Joint analysis of downtime and violations. The occupational safety department uses data from automated equipment performance tracking alongside the results of routine inspections, behavioral safety audits, and shift assignments. At morning production meetings, the reasons why excavators fail to meet targets are analyzed in direct connection with the condition of mining faces and access roads.
• Resource allocation and execution control. Site supervisors' personal plans for eliminating HOS are backed by the allocation of equipment, materials, and budget, approved by the mine director, and defended monthly before the CEO of the regional association. Daily and weekly monitoring at OMS meetings helps promptly identify resource shortages among executors, bringing plan completion rates close to 100 percent.
• Transition to engineering solution control. To avoid spending resources on reactive elimination of violations, the focus shifted to the mine planning stage. Together with the mine surveying department and the technical department, transport berm parameters are designed so that dumping safety berms and fencing the lower edge of the bench do not lead to narrowing of the roadway.

What You Will Learn from This Presentation

• How to organize traffic safety and shift handovers in an open-pit mine given the blind spots of heavy haul trucks prior to implementing electronic collision avoidance systems?
• What formula is used to convert the downtime of overburden and coal-mining excavators caused by poor road conditions into rubles of lost revenue using the stripping ratio?
• How is the procedure for compiling, moderating, and resourcing the monthly register of hazardous operational situations structured at the site and mine management levels?
• How to link automated mining equipment downtime tracking data with production control results at daily operational meetings?
• Why do frontline supervisors tend to underestimate dynamic risks in mining operations, and what tools help engage them in preventive planning?