The short answer
Splitting drilling, blasting, crushing and haulage between four specialist subcontractors can lower each rate on paper. It also creates three handovers at which a problem made by one firm is paid for by the next. One subcontractor for the chain may cost slightly more per item and removes the argument over whose fault the oversize, the idle plant or the short delivery was.
Between a rock face and a road head there are four operations and three points where the stone changes hands. Most of the money lost on the material side of a highway package is lost at those three points, and none of it shows in any single subcontractor's rate.
01The three handovers
| Handover | The typical failure | Who pays when the scope is split |
|---|---|---|
| Drilled hole to charged hole | Holes short, off line or blocked. Shot produces boulders and a toe. | The blaster blames the holes, the driller blames the charge, and you pay for the breaker. |
| Muckpile to hopper | Oversize and uneven supply. Plant runs half empty or bridges. | The crusher claims idle time. The mining side says the plant is slow. |
| Stockpile to road head | Trucks not available on the day, or queued at a loader that is busy. | The haulier bills waiting time. The laying gang stands. |
Each of these is a dispute with two plausible sides. Settling it takes the main contractor's project manager, a meeting, and usually a compromise that leaves the cause in place.
02What a single rate hides and a single firm does not
When one firm holds the chain, the decisions that trade cost between stages are made by somebody who pays for both ends. A tighter drilling pattern costs more at the face and saves more at the crusher. A better haul road costs a grader for a week and saves tyres and cycle time all year. A firm paid only for drilling has no reason to make either choice.
It also changes who you ring. One number, one programme and one monthly reconciliation of tonnes, against four of each.
03When splitting is the right call
- You own a crusher plant and a plant crew, and only the mining is missing.
- The blasting is unusual: beside a live highway, a pipeline or dense housing, where a specialist is worth a separate contract.
- A local transporter with return loads can haul more cheaply than any dedicated fleet.
- The package is large enough that you want two sources so that neither can stop you.
In those cases, write the handovers into the contracts. State the largest piece of rock that may arrive at the hopper and the least tonnage per shift. State the hours trucks will be available and the notice for a change. Without those figures the interfaces are managed by argument.
04What to check before giving one firm the chain
Concentration is a risk too. A single subcontractor short of machines has no second firm behind it. Ask for the equipment register and whether the machines are owned or to be hired in. Ask which other sites those machines are on this year. Ask for a completed package of similar tonnage and the name of the client. A firm that can carry the whole chain will have all three answers ready.