Prime Power & Fuel Cost

How should annual fuel use and refuelling frequency be calculated for a 24-hour mine power plant?

Use hourly mine demand, model-specific fuel data, usable tank capacity, delivery lead time and maintenance windows to plan annual fuel and refuelling.

A prime-power fuel plan cannot be built by multiplying generator rating by 24 hours. Mine demand changes by shift, starting events, dewatering and camp use, while usable tank volume and access conditions constrain delivery.

Engineering scope

Intended audience

Owners, EPC teams and operators planning continuous prime power, remote refuelling or a diesel-storage comparison.

Engineering focus

Bring the operating load, manufacturer fuel table, usable tank volume and delivery conditions into one annual model.

Project deliverable

Monthly and annual fuel ranges, delivery quantity and frequency, normal and adverse autonomy, and a defined safety stock.

Engineering summary

Build an hourly load profile first, then use the proposed engine and genset manufacturer fuel data at the relevant load points. Annual fuel is the sum of operating scenarios; refuelling is governed by usable fuel, verified hourly use and logistics margin.

01

Build a 24-hour load profile

Separate production, shift change, maintenance, night camp demand and emergency dewatering. Continuous loads, intermittent process equipment and motor starts do not create the same fuel result.

  • Record hourly kW or kVA and power factor
  • Separate normal, low-load and peak scenarios
  • Mark crusher, pump and compressor schedules
  • Model dry season, wet season and expansion separately

02

Use fuel data for the proposed model

Fuel litres per hour vary with engine, displacement, emissions configuration and load. Cite the specific bid model and data revision; without it, the result remains a planning range rather than a guarantee.

  • Match the engine and genset configuration
  • Use the relevant load points instead of full-load data only
  • Record fuel, ambient and test conditions
  • Separate estimates from guaranteed values

03

Accumulate hourly use into monthly and annual demand

Multiply hours in each operating block by fuel use at that load, then combine production days, maintenance days and seasonal scenarios. Show base, low-output and high-output cases.

  • State daily, monthly and annual operating hours
  • Include planned service and expected outages
  • Keep production assumptions adjustable
  • Reconcile the model with actual fuel and energy monthly

04

Calculate autonomy from usable tank volume

Nameplate tank volume is not all usable. Suction level, return flow, sediment space, expansion allowance and minimum level reduce available fuel.

  • Separate geometric and usable volume
  • Review day tank and bulk storage together
  • Define high/low level and leak protection
  • Confirm bunding, fire and local storage requirements

05

Set refuelling frequency from logistics risk

Average daily use supports normal delivery only. Wet-season access, supplier lead time, holidays and quality checks determine safety stock and reorder point.

  • Record supplier lead time and round-trip delivery time
  • Use adverse access conditions for safety days
  • Define sampling, filtration and unloading procedure
  • Coordinate delivery with maintenance windows

Inputs the fuel plan must retain

LoadHourly kW/kVA, power factor, combinations and season
GensetEngine model, rating and litres per hour by load
OperationProduction days, service days, annual hours and expansion
StorageBulk tank, day tank, usable volume, levels and transfer rate
LogisticsLead time, route, wet-season interruption, minimum delivery
ReconciliationFuel received, meter energy, running hours and stock variance

Three common calculation errors

01

Rating multiplied by 24 hours

The plant rarely runs at full rating all day, so this distorts purchasing and hides low-load operation.

02

Autonomy based on nameplate tank volume

Minimum level and unusable volume make actual autonomy shorter.

03

Deliveries based on average daily use

The average does not cover road closure, lead-time change or abnormal demand.

Information required before review

  • At least one representative hourly load profile is available
  • Fuel data matches the proposed engine and genset revision
  • Base, low-output, high-output and wet-season cases are separated
  • Usable tank volume and level limits are confirmed
  • Delivery route, lead time and minimum quantity are recorded
  • Monthly fuel-to-energy reconciliation is planned

Have an engineer review fuel autonomy and logistics

Share the hourly load, proposed model, operating hours, tanks, delivery route and seasonal constraints to review the fuel baseline and logistics risk.

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