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Crushing plant payback period calculation
Every technical figure in a crushing and screening proposal eventually collapses into one question: how many years before the money comes back. The crushing plant payback period answers it numerically, and when it is built correctly it lets you compare two machine sizes, two quarry sites, or buying against contracting out on the same scale. When it is built badly, it quietly justifies the most expensive mistake available: a plant whose capacity does not match the site.
What the crushing plant payback period actually measures
Payback is the time a project needs to repay itself out of the cash it generates. Cash is measured, not accounting profit, because non-cash items such as depreciation do not delay repayment, while a spare parts package paid up front leaves the bank account even though it may sit on the balance sheet rather than in the expense column.
The formula itself
Simple payback is total invested capital divided by annual net cash flow. Invested capital is more than the machine price: freight, site preparation, concrete foundations, electrical infrastructure or a generator set, erection and commissioning, and the initial wear parts inventory all belong in the numerator. Any calculation that leaves these out systematically reports a shorter period than reality delivers.
What goes into annual net cash flow
The denominator is annual saleable tonnage multiplied by contribution per tonne. Contribution is the selling price less variable cost: energy, wear parts, oil and filters, operators and maintenance labour, loader fuel and internal haulage. Fixed items such as land rent, insurance and administration sit on a separate line and are deducted from the annual contribution total. If you want that breakdown itemised, the operating cost figures make a clean input for this step.
Utilisation: the variable that breaks most calculations
Catalogue throughput applies while the chamber is fed and the plant is running. On site, maintenance downtime, feed interruptions, weather, full stockpiles and market demand all cut into those hours. The table below isolates utilisation with every other assumption held constant; the values are not absolute years but multiples of the period achieved at ninety percent utilisation.
| Utilisation rate | Annual output (indexed) | Payback period (base = 1.00) |
|---|---|---|
| 90% | 1.00 | 1.00 |
| 75% | 0.83 | 1.20 |
| 60% | 0.67 | 1.50 |
| 45% | 0.50 | 2.00 |
| 30% | 0.33 | 3.00 |
The relationship is inverse rather than linear: halve the utilisation and the period doubles. This is why a plant sized far above the site's real demand can run flawlessly in engineering terms and still return capital slowly.
Linking machine size to annual tonnage
The table below converts catalogue capacities of the General Makina mobile range into annual output. The worked assumption is 2,000 scheduled hours per year at seventy percent utilisation, that is 1,400 productive hours, with the midpoint of each capacity range used.
| Model | Catalogue capacity | Maximum feed size | Worked annual output |
|---|---|---|---|
| General 640 | 40-70 t/h | 500 mm | 77,000 t |
| General 800 | 80-120 t/h | 600 mm | 140,000 t |
| General 950 | 120-180 t/h | 800 mm | 210,000 t |
| General 03 | 250-350 t/h | 900 mm | 420,000 t |
Redo that column with your own numbers: divide your annual saleable tonnage target by the catalogue capacity to see how many productive hours you need. Well under 1,400 hours means the machine is oversized; well above it means a second shift or the next model up belongs in the discussion.
Three things simple payback hides
First, the time value of money: simple payback treats cash in year five as equal to cash in year one, so a discounted payback period is always longer. Second, residual value; the plant does not become scrap the day it has repaid itself, and its second-hand worth rarely enters the decision. Third, working capital, which is cash locked into inventory, receivables and spares yet invisible in the formula. These three sit underneath every other calculation on the investment and cost side of a project.
Frequently asked questions
What payback period counts as acceptable
There is no universal threshold. The period must be shorter than both the reserve life of the deposit and the term of the financing; a seven-year reserve cannot support an investment that repays in nine.
Why is the calculation different for mobile and stationary plants
Stationary installations add foundations, conveyor structures and electrical infrastructure to the numerator. Mobile plants shrink those items but spend production hours on relocation and set-up, which reduces the denominator instead.
How do you compare renting with buying
Renting involves almost no invested capital, so payback cannot be computed; the comparison is made on total cost per tonne. Purchasing becomes cheaper per tonne above a certain annual volume, and that break-even volume must be found with the site's real running hours.
How much does the energy price move the result
Energy is the most volatile element of variable cost. Build the calculation on at least two energy scenarios and treat the gap between the two resulting periods as your decision range rather than trusting a single figure.
Instead of reducing the decision to one number, write three scenarios for utilisation and contribution. If even the worst case still fits inside the financing term, the case is sound. Send us your site data and tonnage targets and our engineering team will size the configuration with you.
Definitions of technical terms: Glossary
