Find out what the crushing cost per tonne actually consists of: energy, wear parts, labour and capital recovery. Compare quotations based on the same CSS and product specifications.
Crushing cost is not a single figure—it is the sum of energy, wear metal, labour and capital recovery, divided by the tonnes of usable product you sell. For a quarry owner, the only cost that matters is the delivered cost per tonne of finished product meeting the specified requirements, not the cost per tonne of material fed into the crusher. Before you compare quotations or alter process parameters, you must determine the particle size distribution, the work index of your rock, and the moisture content; without these three pieces of information, any cost figure is, at best, an estimate and, at worst, a guess.
This page provides you with a decision-making framework. It will not tell you that «crusher X costs $1.50 per tonne»—no honest editor can do that, because the evidence depends on your site. What it will do is show you which factors reduce costs, which cost items you are likely to be underestimating, and what data you must collect before you can make a final decision.
1. Energy (power) consumption
Energy is the most obvious cost item, but it is rarely the largest. The specific energy required to reduce rock from one size to another is determined by the rock’s Bond work index. Softer limestone will consume significantly less energy per tonne than greywacke or granite. To estimate energy costs, you need the work index in kWh/t, which is a laboratory measurement – not something you can assume based on the rock’s name.
2. Wear parts (lining and blow bar life)
This is where quarry owners most often underestimate costs. Wear rates depend on the abrasiveness of the rock (measured by the Abrasion Index), the crusher setting, and the feed grading. A jaw crusher with a tight closed-side setting (CSS) will consume more wear metal per tonne than the same machine with a looser CSS, because the rock is subjected to more crushing events. If a supplier quotes a wear cost without asking for your abrasion index, treat that quote as incomplete.
3. Labour and maintenance
Planned maintenance hours are a fixed cost; unplanned stoppages are the real risk. A crusher that is difficult to access for liner changes will cost more in labour hours over the course of a year than the difference in purchase price between two competing models. Factor in the cost of the replacement crew, crane hire and the loss of production during the replacement.
4. Capital recovery
If you operate the plant for 10 years and process 8 million tonnes, the crusher’s purchase price represents a small fraction of the total cost per tonne. If you only operate the plant for 2 years before a major overhaul, it represents a very large fraction. The period over which you depreciate the machine is a management decision, not an engineering fact, but it changes your cost per tonne dramatically.
Your crushing costs are primarily determined by wear life, not by the purchase price. Two similar crushers can have a 15–20% difference in liner life when processing the same type of rock, depending on the design of the crushing chamber and the material’s angle of impact. A machine that is easy to adjust and maintain—as measured by the time taken to change liners—will save more money over five years than a machine that costs 10% less but takes twice as long to service.
The design of the counterweight and rotor in an impact crusher affects how evenly the wear parts are worn down. Uneven wear means you are discarding usable metal and replacing parts before their theoretical service life has come to an end. You cannot verify this from a brochure; you need to examine wear profiles from actual installations processing the same type of rock.
The single biggest mistake: quoting a price without a defined CSS. The closed-side setting determines the product size, the reduction ratio and the wear rate. If you require a fine-grained product, expect a higher cost per tonne. If you require a coarse sub-base product, the cost per tonne will be lower. Compare quotations only where the CSS and product specifications are the same.
Total cost per tonne = (Energy cost + Cost of wear parts + Labour + Maintenance + Capital recovery) ÷ Tonnes of sellable product
Most quarry owners make two mistakes. Firstly, they divide by feed tonnes instead of tonnes of saleable product. If your operation produces 20% of fines that you cannot sell, your cost per sellable tonne is 25% higher than the raw calculation indicates. Secondly, they fail to include the cost of the conveyors and the screen media, which can account for 5–10% of the total plant operating cost.
A worked example (with placeholder values that you must replace with your site’s data):
This article cannot provide you with verified figures for SUHMAN equipment as the conditions at your site are not known. To obtain a meaningful figure, you must provide the material work index, abrasion index, moisture content and feed gradation; without these, any cost calculation will be merely an estimate.
Use this table as a template for your site’s data—fill in your own figures; do not rely on someone else’s:
| Cost driver | What the buyer must provide | Why it affects your cost per tonne |
|---|---|---|
| Bond work index (kWh/t) | Test report from a certified laboratory | Calculates energy consumption for your specific type of rock |
| Abrasion index | Test report or historical liner service life from a nearby site | Determines the cost of wear-resistant metal, the largest variable cost item |
| Feed gradation (maximum size, % of fines) | Sieve analysis of the quarry floor | Production of oversized feed stalls; excess fines result in wasted crushing energy |
| Moisture content | Field measurements, seasonal range | Affects screen efficiency, throughput and blockages |
| Required product specifications | Sieve curve and flakiness target | Specifies CSS, which drives wear and energy |
| P90 operating hours per year | Your planned timetable | Determines capital recovery per tonne |
| Liner change time (hours) | Ask the supplier for a documented procedure | This is the hidden labour cost over a five-year period |
This table is a checklist, not a specification sheet. The blank cells are intentional. If a supplier fills in those cells with figures before asking you for the details above, those figures are likely based on a different rock type or product specification from yours.
A supplier’s quotation typically includes energy costs and wear parts for a reference material with a known work index and abrasion index. Your rock is different. More importantly, the quotation rarely takes into account your site-specific screen efficiency, conveyor availability or downtime caused by upstream equipment. The discrepancy between the quote and reality is largely down to differences in the assumptions made about your feed. Provide the supplier with your actual sieve analysis and a rock test sample; then the quote will be comparable. .
Not automatically. A larger crusher operating at partial load has a higher capital recovery cost per tonne and a similar or slightly higher wear cost, as the crusher is not operating within its most efficient cavity. The best approach is to match the crusher to the P80 of your feed and your required product P80. Oversizing a crusher to «allow for future growth» rarely pays for itself unless you plan to increase feed tonnage within two years.
In hard rock quarries, wear parts are the main cost driver. In concrete and asphalt recycling, steel rebar and contaminants in the feed significantly reduce wear life and increase the risk of downtime due to blockages. A crusher configured for quarry operations may require a different rotor and apron configuration for recycling applications. If you operate in both applications, calculate two separate cost-per-tonne figures—do not average them.
There is no universally safe percentage. For abrasive granite, wear parts can account for over 50% of the total operating cost; for soft limestone, this figure can be as low as 20%. Instead of tracking a percentage, track the cost of wear parts per tonne per millimetre of CSS. This ratio tells you whether your machine setup is cost-effective before you switch suppliers. A 15% difference in this ratio between two setups represents a greater saving than any discount you can negotiate on the machine.
A VSI is often added to improve the particle shape in the fine fraction, not to reduce costs. Adding an extra crushing stage always increases the cost per tonne, as it adds energy and wear costs without increasing the volume of product. The rationale for a VSI is the higher selling price of the shaped product, not lower operating costs. Only install a VSI if the premium on the shaped product covers the additional cost per tonne. .
This framework applies to conventional quarry circuits with a stable feed and a defined product specification. It does not apply to short-term contract crushing involving varying materials, to very high-moisture clayey feeds that cause severe screening problems, or to installations where the power supply is unreliable—in such cases, the cost model changes because downtime becomes the dominant cost factor, rather than wear or energy. In such cases, you need to take into account the cost of generator fuel and the reduced throughput caused by wet, sticky material before comparing any equipment.
Information required to reach a final decision: To convert this framework into a specific cost figure for your site, you must provide the measured output from an existing circuit (tonnes per hour, product grade and test duration), the full feed conditions (material type, hardness, moisture content, maximum feed size), the sequence of equipment you plan to use, and the project location, as local electricity tariffs and labour rates significantly affect the calculation. Without this information, SUHMAN’s editors can explain the trade-offs, but only your site data can determine the cost per tonne.
