Surface Blasthole Drill Productivity
Meters per shift, holes per shift and cost per meter from the rock you are
drilling and the pattern you are drilling to. Pairs with Surface Bench Blast Pattern: that one gives you the
pattern, this one tells you what it costs to drill it.
Surface bench drilling only: vertical production holes to a bench. The
published rates are for surface units and do not describe underground development drilling.
Step 1: The rock
Two choices set the penetration rate. Nothing else moves it as much.
Step 2: The hole and the pattern
Take these straight from Surface Bench Blast Pattern.
Step 3: The shift
The gap between penetration rate and meters per shift is where the money goes.
Step 4: Your costs
These are yours, not the handbook's. The source says so: they come from the project.
| Step | Value | Where it comes from |
|---|
Where the shift goes
What a meter costs
Penetration rate by rock strength and fabric
| Rock fabric condition | ||||
|---|---|---|---|---|
| Stable, uniformly competent ground | 55.0 | 33.5 | 30.5 | 24.5 |
| Competent rock, fractured collar zone (top 0.6 to 1.2 m) | 49.5 | 30.0 | 27.5 | 22.0 |
| Closed joints, fractured collar zone (top 0.6 to 1.2 m) | 42.0 | 25.5 | 23.5 | 18.5 |
| Open joints, fractured collar zone (top 0.9 to 2.4 m) | 33.5 | 20.5 | 18.5 | 15.0 |
| Heavily jointed, poorly cemented (top 1.2 to 3 m) | 27.0 | 16.5 | 15.0 | 12.0 |
SME Mining Engineering Handbook, Table 7.2-2, p. 440, in meters per hour. Read down for strength and across for fabric: the two together span 55 m/h at best to 12 m/h at worst, a factor of more than four. Fabric matters about as much as strength does, which is not how most rate-of-penetration estimates are made.
Drilling methods and what they are for
| Method | Diameter, mm | Typical depth, m | Typical rate, m/h | Accuracy | Source |
|---|---|---|---|---|---|
| Top hammer pneumatic jackleg | 25-50 | under 4 m | 60 | 2-5 | Table 7.2-1 p. 439 |
| Jumbo | 37-100 | 4-10 m | 100-200 | 1-3 | Table 7.2-1 p. 439 |
| Surface crawler-mounted drill | 50-150 | 5-30 m | 20-150 | 1-3 | Table 7.2-1 p. 439 |
| Top hammer hydraulic jumbo | 37-125 | 4-20 m | 30-120 | 2-3 | Table 7.2-1 p. 439 |
| Down-the-hole | 75-150 | 10-50 m | 20-80 | 3-5 | Table 7.2-1 p. 439 |
| Rotary, small (MD6200 class) | 127-200 | to 47.5 m multi-pass | n/a | n/a | Cat handbook p. 3-4 |
| Rotary, mid (MD6250 class) | 152-250 | to 53.6 m multi-pass | n/a | n/a | Cat handbook p. 3-4 |
| Rotary, large (MD6310 class) | 203-311 | to 74.6 m multi-pass | n/a | n/a | Cat handbook p. 3-5 |
| Rotary, largest (MD6380 class) | 251-381 | multi-pass | n/a | n/a | Cat handbook p. 3-5 |
Percussive methods from the SME Mining Engineering Handbook, Table 7.2-1, p. 439; its rate column is a range across all rock types, so it is a sanity check on the figure from the table above rather than a substitute for it. That table stops at 150 mm, which does not reach a normal production bench hole, so the rotary classes come from the Caterpillar Performance Handbook rotary drill specifications, pp. 3-4 and 3-5. Caterpillar publishes no penetration rate with them, so no rate check is applied to a rotary selection rather than one being invented.
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Worked with the values this page loads with, so the method can be checked against the cited source without entering anything. Change any input above and the calculator recomputes; the numbers below stay as a fixed reference case.
- 582
- 17.1
- $5.44 / ft
| Penetration rate | 90.2 ft/h | Medium hard rock, competent rock, Table 7.2-2 p. 440 |
| Hole depth | 34.0 ft | your input, bench plus subdrill |
| Time on bottom per hole | 22.6 min | depth ÷ penetration rate |
| + move and set up | 6.0 min | your input |
| = cycle per hole | 28.6 min | |
| Shift length | 12.0 h | rostered |
| × mechanical availability | × 0.85 | your input |
| × utilization | × 0.80 | your input |
| = hours actually drilling | 8.16 h | |
| = holes per shift | 17.1 | working hours ÷ cycle per hole |
| = meters per shift | 581.7 ft | holes × depth |
| Rig cost per shift | $2640 | $220/h × 12.0 rostered hours |
| Bit cost per shift | $524 | 581.7 ft ÷ 5000.0 ft bit life × $4500 |
| = cost per meter | $5.44 / ft | both costs ÷ meters drilled |
| Rock broken per hole | 377 yd³ | burden × spacing × bench |
| Rock broken per hole | 683 t | × bank density |
| = drilling cost per ton | $0.271 | cost per hole ÷ tons per hole |
Estimating aid only. This is not an engineering design and not a substitute for the judgment of a competent or qualified person. Verify every result against the cited source and your own site conditions. Full terms and disclaimer.