Start with the hole's purpose
Face drilling jumbo vs long-hole drilling rig is a choice between different drilling duties before it is a comparison of machine sizes. A face jumbo addresses holes at a development face; a production long-hole rig addresses the longer production holes specified by the mining plan. An overlapping hole diameter does not make the two machines interchangeable.
Epiroc separates face drilling for underground mining and tunnelling from production long-hole drilling in its official equipment overview. That distinction is useful when preparing an inquiry: describe the required work first, then ask which configuration fits it. A request for an underground drill with a particular diameter and motor power leaves too much of the actual duty unspecified.
Development and production ask different questions
For a development-face inquiry, the starting information is the face geometry and the required hole arrangement. The supplier needs to understand where the feed must reach within that working space. A specification that lists a long rod but does not establish the relevant positioning envelope leaves the central fit question unanswered.
For production long-hole work, the inquiry shifts toward the required hole lengths, orientations and rod-handling arrangement. A rig must be assessed as a drilling system within the available working space. The carrier's travel dimensions alone cannot show whether the feed can be positioned for the proposed duty.
Sandvik also identifies underground development and production as distinct applications in its equipment range. Use those categories as a first sorting step, then compare the exact model and configuration. Equipment-family labels are too broad to establish a machine's complete capability.
Sandvik: underground development and production drill rigs ↗
Keep feed length, rod length and hole depth separate
Three dimensions are easily confused in a quotation. Total feed length describes the physical feed assembly. Rod length describes a piece of drill steel. Hole depth describes a drilling capability under the stated configuration. They answer different questions, so each deserves a separate field in a comparison sheet.
The ZDFJ76A1 source illustrates the distinction. Its feed section lists a total length of 5850 mm, a drill rod length of 3700 mm and a hole depth of 3500 mm. Reading the first value as achievable hole depth would misrepresent the document. Reading the rod length as the exact finished hole depth would also replace one stated parameter with another.
Long-hole specifications introduce a further distinction because the stated depth can involve a string of rods. An individual rod does not have to equal the final hole length. The inquiry should identify the selected rod system and the documented drilling depth together, without calculating a guaranteed depth simply by multiplying a storage count by a rod length.
Read ZDFJ76A1 as a face-jumbo example
The supplied ZDFJ76A1 technical document describes a single-boom electro-hydraulic jumbo for underground face drilling and tunnelling. Its table gives a 32–76 mm hole diameter range. Together with the feed and depth entries above, this creates a model-specific starting point for a development inquiry. It does not define the capability of every machine bearing a similar name.
The source also describes an optional telescopic feed arrangement for confined bolt-hole work. Optional equipment should remain identified as optional. Its mention does not turn the published standard feed values into a different configuration, and it does not establish suitability for every ground-support task.
Some source fields need clarification, including differing coverage descriptions. Those values are not used here to promise that the machine will cover a particular tunnel section. For an actual purchase comparison, ask for an approved configuration drawing showing the required face and positioning envelope rather than relying on an ambiguous coverage figure.
Read ZDTC64 and ZDTC89-2 as separate production references
The ZDTC64 source describes underground production long-hole drilling. Its specification lists a 45–64 mm hole diameter range, rod lengths of 915–1525 mm and drilling up to 20 m. These values belong together under ZDTC64. The shorter individual rod length and the longer stated drilling depth are not competing claims; they describe different parts of the system.
The ZDTC89-2 reference describes an automatic rod-handling arrangement. Its table records 32+1 rods, rod lengths of 1500–1800 mm and mechanized drilling up to 52 m. These are documented reference entries, not a prediction that every hole will reach the maximum depth in every formation or orientation.
Keep the models in separate rows. The 52 m figure must not migrate into a ZDTC64 inquiry, and the ZDTC64 diameter range must not be assigned to ZDTC89-2. The latter document contains differing diameter wording, so this guide does not resolve that range by choosing the larger number. Request confirmation for the proposed tooling and configuration.
Diameter overlap does not decide the shortlist
Compare the cited ZDFJ76A1 and ZDTC64 diameter ranges and an overlap is visible. That does not erase the difference between their duties or depth entries. A buyer selecting solely on diameter could shortlist a machine without resolving how it will perform the required drilling arrangement.
The same caution applies to an isolated power figure. Even when two documents list similar rock-drill power, the buyer still needs the feed, positioning and rod-handling details that define the proposed system. A shared number is not evidence of equal hole accuracy, equal output or interchangeable use.
A useful shortlist therefore starts with the intended duty, required hole geometry and working-space evidence. Only candidates that address those requirements should move into a more detailed commercial comparison. This prevents a lower price on an incomplete specification from being mistaken for a better offer.
Ask for evidence that matches the proposed configuration
Send the intended development or production duty, required hole diameters and depths, and the relevant working-space drawings. Specify whether the dimensions describe the travel route or the drilling position. Include available site utility information so the supplier can identify the applicable machine arrangement. These inputs support a technical review; they are not operating settings.
Ask the quotation to identify the exact model, feed, rod lengths, handling arrangement and included options. Where a reference document lists alternatives, the offer should state which alternative applies. An unresolved field should be marked for confirmation. Keeping it visible is more useful than blending specifications from neighbouring models.
For performance claims, request the conditions and measurement basis. A quoted penetration rate without rock conditions, tooling and a clear definition cannot establish completed production for a shift. This guide therefore does not reuse the unqualified drilling-speed claims in the supplied product documents.
Keep a record of the quotation revision as well. A changed feed or rod-handling option can make an earlier comparison obsolete even when the model name stays the same. The final review should refer to one coherent configuration, with its drawings and specification sheet attached, so that both parties are discussing the same equipment.
Make the comparison answer one purchasing decision
If the immediate requirement is development-face drilling, assess the face-jumbo configuration against that duty. If it is production long-hole drilling, assess the production rig and its rod system against the proposed holes. Where a project has both duties, prepare two requirement sets before deciding how the equipment package should be organized.
The comparison then has a clear purpose: establish which documented configuration addresses each requirement and which details remain open. Product pages supply the reference values. The purchasing analysis connects those values to a defined duty, without converting a maximum specification into a universal performance promise.
Frequently asked questions
Can the same hole diameter justify choosing either type?
No. Diameter is only one selection field. Development-face and production long-hole requirements also differ in hole geometry, depth, positioning and rod handling. Assess the complete proposed configuration against the intended duty.
Is feed length the same as drilling depth?
No. In the ZDFJ76A1 reference, total feed length is 5850 mm, rod length is 3700 mm and hole depth is 3500 mm. Each number must keep its original label when comparing quotations.
Does ZDTC89-2's 52 m reference apply to ZDTC64?
No. The supplied ZDTC64 document lists drilling up to 20 m. The ZDTC89-2 document lists mechanized drilling up to 52 m for its own arrangement. Neither maximum establishes actual results for an unspecified application.