An air-leg rock drill can be a practical development-heading tool when the approved mine method, opening size and access do not justify or permit a larger mechanized drill. The buying decision should not begin with a familiar model name. It should begin with the heading, the number of holes and tools expected to operate, the available compressed air and water at the face, the drill-steel system, the work sequence and the maintenance support that can actually be sustained underground.
For procurement, treat the setup as one chain: air supply → distribution and isolation → hose and line oiler → rock drill and air leg → shank, steel and bit → flushing → operator and approved work area. A weak link anywhere in that chain can look like a weak drill.
Define the heading before requesting a model
The supplier needs enough context to distinguish a restricted development heading from a general underground drilling request. Record the heading dimensions and access restrictions, drilling directions, target hole diameter and depth range, rock description, water conditions, planned number of simultaneous drills, shift pattern and the site's approved handling method.
Do not ask a supplier to design the blast round or ground-support sequence through a rock-drill quotation. Those decisions remain with competent mine engineering and the site's legal and safety controls. The RFQ should translate an approved operating need into equipment interfaces, not create the operating need.
| Heading input | Why the supplier needs it |
|---|---|
| Working envelope and access route | Determines whether the drill, air leg, steel and hoses can be positioned and transported |
| Drilling direction and collar range | Helps match the feed arrangement and handling method |
| Hole diameter and depth range | Controls bit, steel length and expected drilling setup |
| Tools operating at once | Drives air-distribution and compressor demand |
| Air and water data at the face | Prevents selection from relying on compressor or pump nameplates alone |
| Existing shank, steel and bit stock | Shows whether compatibility or standardization is required |
| Shift and maintenance plan | Defines standby units, spare parts and service documentation |
Verify air at the working face
Catalog air consumption is an input, not the complete compressor decision. Add the simultaneous tool count, real duty, distribution loss, hose route, other air users and the minimum dynamic pressure required by the selected manufacturer. Measure or estimate at the face rather than assuming pressure at the compressor equals pressure at the drill.
Long or undersized hoses, restrictive couplings, leaks and an overloaded distribution header can reduce drilling performance. Include hose internal diameter, length, coupling type, working pressure and isolation/restraint requirements in the order. If several headings share one system, state which tools can run at the same time.
Match the air leg and drill steel to the working cycle
The air leg must fit both the drill and the approved positioning method. Confirm its retracted and extended geometry, connection, control arrangement and service parts. A longer feed range is not automatically better if it cannot be positioned or controlled inside the heading.
For tapered systems, specify the shank, H22 steel lengths, taper angle and bit diameter together. Plan starter and follow-on steel around the approved hole depth and available handling space. If the mine already has steel and bits, send photographs, markings and controlled dimensions rather than asking the supplier to identify compatibility from a nickname.
Build the mobilization package
A heading package may include the drill, air leg, line oiler, air and water hoses, approved couplings, hose restraints, drill steels, bits, basic service tools, initial wear parts and documentation. The exact contents depend on the site and offered model, but each quotation should clearly state what is included and excluded.
Create a readiness table before shipment:
| Package area | Ready when | Hold when |
|---|---|---|
| Drill and air leg | Exact identities and interface are documented | Model or leg connection is ambiguous |
| Air system | Flow, pressure basis, hoses and couplings are defined | Only compressor horsepower is known |
| Drill string | Shank, steel, taper and bit match | Components are described only as “standard” |
| Flushing | Water connection and site supply are controlled | Hose/thread/pressure information is missing |
| Spares | Critical wear items and part references are listed | Spare request is a generic box with no model link |
| Documents | Operating, maintenance and parts information is included | Training and service information are unavailable |
RFQ fields
Send the heading/application, hole range, rock and water conditions, operating orientation, simultaneous drill count, air and water data at the face, hose lengths, existing drill-steel interfaces, required package quantity, shifts, destination, packing needs and requested inspection evidence.
Use the Rock Drills collection as the commercial route and submit project data through Request a Quote. PerfoMax should confirm the exact offered configuration; this guide does not promise any particular model or accessory.
FAQ
How many air-leg drills should one heading buy?
Base the quantity on tools operating at once, standby needs, repair turnaround, shift coverage and compressor capacity. There is no universal ratio.
Can the compressor be selected from one drill's catalog CFM?
No. Use simultaneous demand, duty, losses, other air users and dynamic pressure at the face.
Should the supplier choose the hole pattern?
No. The mine's competent engineering and approved procedures control the drilling and blasting design.