搜索历史清除全部记录
- All
- Product Management
- News
- Introduction
- Enterprise outlets
- FAQ
- Enterprise Video
- Enterprise Atlas
Comparison of Return on Investment Between Single-Arm and Double-Curve-Arm Rock-Drilling Rigs
Release time:
2026-09-23
Source:
Author:
Summary:
Single-arm and double‑boom rock‑drilling rigs serve distinct roles in tunneling and mining operations, and their return‑on‑investment analyses must be evaluated holistically, taking into account actual cross‑section dimensions, construction cycle efficiency, and operating costs. Single‑arm rigs excel in low acquisition costs and flexible relocation, making them well suited for small to medium‑size headings or auxiliary drilling tasks; by contrast, double‑boom rigs, with their ability to drill simultaneously from both booms and to cover an exceptionally wide area, deliver higher overall productivity in large‑cross‑section tunnels. Selecting the appropriate equipment requires a comprehensive assessment of project scale, budgetary constraints, and construction timelines to ensure a scientifically sound alignment between investment and output.
I. Initial Investment and Applicable Cross-Sections
The purchase price of a single-arm rock‑drilling rig typically ranges from RMB 500,000 to 1.5 million, making it suitable for small and medium‑sized mine drifts and tunnels with cross‑sections of 10–30 m². Specifically, the entry‑level tire‑mounted single‑arm rig, with a reference price of approximately RMB 1.2 million, is designed for excavating gold‑mine drifts measuring 2.6 × 2.6 m. Double‑arm rock‑drilling rigs (including those with double‑curved booms) generally cost between RMB 3 million and 6 million, catering to railway tunnels, highway tunnels, and large hydraulic tunnels with cross‑sections of 30–80 m². The double‑curved‑boom model has an overall weight of about 28–29 tonnes, dimensions of roughly 9.5 × 2.5 × 3.6 m, and a maximum working envelope of 16 × 11 m, covering an area of approximately 195 m², thereby adapting well to bench‑cutting construction methods. In tunneling operations, double‑arm rigs are the mainstream choice, striking a favorable balance between efficiency and economic viability.
II. Comparison of Production Efficiency
Drilling efficiency is a key factor in determining project duration. Taking a typical cross-section with 100 blast holes, each 3.5 m deep, as an example: a single‑arm rig requires approximately 2 minutes per hole, for a total drilling time of 200 minutes (about 3.3 hours). In contrast, a dual‑arm rig operates both booms simultaneously, reducing the time per hole to 1.5 minutes and cutting the total drilling time to roughly 75 minutes (about 1.25 hours). Based on these figures, the dual‑arm system is approximately 60% faster than the single‑arm setup; moreover, as the number of holes increases, the proportion of auxiliary time decreases, leading to even more pronounced efficiency gains. For small cross‑sections, a single‑arm rig takes about 2.5 hours per cycle to drill 30 holes, each 2.7 m deep, achieving a penetration of roughly 2.5 m per cycle. By contrast, a dual‑curved‑arm rig can drill at speeds 5–6 times that of manual pneumatic drills, with a maximum penetration of up to 4.8 m per hole per cycle, representing an approximate 25% increase in drilling speed in hard rock.
III. Composition of Operating Costs
Operating costs are a central component of return‑on‑investment analysis. For rock‑drilling rigs, operating expenses consist primarily of labor, electricity, and materials; among these, material costs—covering drill bits, drill rods, shank adapters, seals, and other consumables—account for roughly 70% of total monthly construction expenditures. However, mechanized operations can significantly reduce labor costs: traditional methods require 15 workers operating handheld pneumatic drills, whereas a single‑arm rig needs only 1–2 operators, and a dual‑arm rig likewise requires just 1–2. The dual‑arm rig has a total installed power of approximately 125 kW, with two main motors each rated at 55 kW, resulting in an overall electrical system capacity of 125 kW. Dual‑curved‑arm models can be equipped with a diesel‑electric hybrid drive system, enabling pure electric mode during tunneling and reducing overall energy consumption by 15%–20%. In terms of maintenance and service costs, the hydraulic system of a dual‑arm rig is more complex than that of a single‑arm unit, with additional drill‑arm joints, cylinders, and valve assemblies, leading to a higher number of potential failure points and correspondingly higher maintenance expenses. Spare‑parts inventory typically amounts to about 5% of the equipment’s asset value.
IV. Payback Period Analysis
The payback period for a single‑arm rock‑drilling rig typically ranges from 6 to 12 months. A cost‑effective, small‑section single‑arm rig priced at RMB 1.2 million requires replacement of only one drill bit after 20 days of full‑face tunneling in gold mines, with low consumable costs and significantly higher efficiency compared to manual drilling. According to a comparative analysis of tunneling costs at the Xiaowanggou Iron Mine, the rig reduces per‑meter excavation costs by RMB 914.87 relative to manual drilling; when tunnel advance exceeds 3,269 meters, using a rig becomes more economical than manual methods. Based on this cost‑saving estimate, the single‑arm rig can recoup its capital investment in approximately 6.4 months, assuming an average advance rate of 232.5 meters per month.
The payback period for two-boom and three‑boom rock‑drilling rigs is relatively long, typically ranging from 1.5 to 3 years, primarily constrained by the substantial capital investment and the scale of the project. Two‑boom rigs are best suited for larger projects with tunnel lengths exceeding 300 m and cross‑sectional areas greater than 30–80 m². In large railway tunnel projects—such as the Shenyang–Baishan High-Speed Railway—the two‑boom, three‑stage drilling method has enabled a maximum advance per cycle of 4.7 m, reduced drilling time to under 3 hours, and achieved an average monthly excavation rate of over 200 m. Compared with conventional methods, this approach significantly cuts drilling time, with the primary return on investment realized through a marked reduction in construction duration.
For a two-boom tunneling machine to achieve a reasonable return on investment, the following conditions must be met: single-heading advance rates of no less than 3,000 m (roughly equivalent to the annual excavation volume of a small- or medium-sized tunnel), rock hardness of medium grade or higher (Proctor coefficient f ≥ 6), and cross-sectional areas exceeding 30–40 m². When the total project length is less than 1,000 m or the cross-section is smaller than 20 m², the two-boom machine is unlikely to generate sufficient economic returns, and the payback period may extend to more than three years.
V. Special Advantages and Economic Benefits of the Hyperbolic-Arm Trolley
The core value of the double‑curved‑arm tunneling rig lies in its unique construction‑method adaptability and multi‑process integration capabilities, enabled by its curved‑arm architecture. The curved arm can operate below the horizontal plane, meeting the requirements of two‑stage and three‑stage tunneling while overcoming the limitation of conventional rock‑drilling rigs that cannot execute invert‑arch excavation. The dual‑arm design significantly expands the working envelope—by more than 40%—thereby reducing the frequency of equipment repositioning during construction. A coordinated dual‑arm control system shortens single‑cycle operation time by approximately 30%. Under complex geological conditions, this rig can also perform support‑drilling tasks such as systematic rock bolts and advance pipe sheds, offering versatile functionality that boosts equipment utilization and cuts auxiliary‑equipment costs. Models equipped with a hybrid power system enable zero‑emission operations, helping to lower ventilation and air‑exchange expenses in high‑altitude environments and gas‑prone tunnels.
VI. Selection Recommendations
Comparison Dimension: Single-Arm Rock-Drilling Rig vs. Double-Curve-Arm/Double-Arm Rock-Drilling Rig
Purchase price: approximately RMB 500,000–1.5 million; approximately RMB 3–6 million.
Applicable cross-sections: 10–30 m², 30–80 m²
Drilling efficiency: approximately 3.3 hours for 100 holes; approximately 1.25 hours for 100 holes (with dual-arm coordination).
Operator: 1 person, 1–2 persons
Installed power: approximately 55 kW; approximately 125 kW (including two motors)
Economic payback period: approximately 6–12 months; approximately 1.5–3 years (requires a project volume of ≥3,000 m³).
Applicable scenarios: small to medium cross-sections, auxiliary drilling, and frequent relocation; large‑cross‑section long tunnels, bench method construction, and invert excavation.
Core Advantages: Low procurement costs, high maneuverability and flexibility, and simple maintenance; high efficiency, broad coverage, and multi‑process integration.
In tunneling projects, the cross-sectional area is a key factor in determining the selection of support equipment: for sections ranging from 10 to 30 m², single-boom units should be prioritized, while for sections between 30 and 80 m², dual-boom units are more appropriate. Dual-boom rigs offer particularly significant overall benefits in large‑section tunnels, making them especially well suited for large‑scale excavation projects with long tunnel lengths and stringent schedule requirements. By contrast, single-boom rigs, with their lower initial capital outlay and greater mobility, can deliver superior economic returns in medium‑ and small‑scale projects or short‑length headings.
RELATED INFORMATION
Contact Us
Changsha Base:Hunan Zenxon Heavy Industry Technology Co., Ltd.
Address: Jinrong Tongxin International Industrial Park, Changsha High-tech Zone
Loudi Base:Hunan Haoda Heavy Industry Technology Co., Ltd.
Address: Loudi Avenue, Loudi High-tech Industrial Development Zone, Lianyuan City, Loudi City, Hunan Province
Telephone:400-186-0868
E-mail:3804246750@qq.com
E-mail:19967177733@163.com
0
Consult now
WeChat Public Number
TikTok