Explosion-Proof Crane Selection for Mining & Coal
Key Takeaway Mine and coal industry crane selection falls into three scenarios: for underground coal mines, choose the HB/KB type explosion-proof electric hoist (Ex dⅠ/MA certification/1–25 t/CNY 20,000–200,000/cast steel flameproof enclosure); for coal preparation plants, select the QD type overhead crane or MG type gantry crane with Ex tD A21 dust explosion-proof configuration (32–100 t/CNY 400,000–2.5 million/IP55 + C4 anti-corrosion); for open-pit mines and maintenance workshops, a general-purpose overhead crane (16–50 t/CNY 300,000–1.2 million/double hook + VFD + remote control) is suitable. Note that underground mines require Ex dⅠ (coal-mine-specific), while non-coal mines may use the Ex dⅡ series.
The mining and coal industry is one of the most demanding application fields for explosion-proof crane requirements. Underground coal mines carry the risk of gas (methane) explosions, requiring coal-mine-specific Ex dⅠ explosion-proof equipment. Coal preparation plants face coal dust explosion hazards and must be configured to dust explosion-proof standards. Open-pit mines and maintenance workshops can use general-purpose cranes. This article breaks down the selection essentials for three scenarios: underground explosion-proof operation, coal preparation plants/open-pit mines, and mining equipment maintenance.
Underground Explosion-Proof: Ex dⅠ + MA Certification
Underground coal mine environments carry the risk of gas (methane, explosive range 5–15%) and coal dust explosions. Any electrical equipment must pass coal mine safety certification (MA certification) and meet the Ex dⅠ explosion protection class. Typical installation positions for underground mine cranes include: central substations (transformer/switchgear cabinet hoisting for maintenance), main drainage pump rooms (pump motor maintenance), and mechanical repair chambers (mining equipment servicing).
Recommended Model: HB type mining explosion-proof electric hoist (lifting capacity 1–25 t, lifting height 6–12 m) and KB type mining explosion-proof electric hoist (large tonnage/slow speed, 10–25 t). The HB/KB types use the Ex dⅠ Mb flameproof rating — the motor and electrical enclosure feature a ZG230-450 cast steel housing (flameproof joint gap ≤0.2 mm, reference pressure 1.0 MPa), and the motor is a YBK3 series mining explosion-proof motor. The travel mechanism uses a manual trolley (rail-mounted) or gear drive (rail-less). The matching control box is a mining flameproof enclosure (Ex dⅠ Mb). The HB type mining explosion-proof electric hoist is priced at approximately CNY 20,000–200,000 (depending on tonnage).
Mounting Type: Underground cranes are typically installed on pre-embedded I-Beam rails mounted to the tunnel roof or chamber ceiling, with the rail secured to the roof via anchor bolts. Before installation, the load-bearing capacity and anchoring force of the roof rock layer must be verified. Due to limited underground space, the crane's overall dimensions and minimum clearance must be confirmed before purchase.
MA Certification Maintenance: The MA coal mine safety sign certificate has a validity period of 5 years and must be re-certified upon expiry. The user unit must check quarterly that the explosion-proof marking and MA certificate remain within their validity period, and test the flameproof enclosure sealing surfaces and cable entry sealing semi-annually. Maintenance of underground mine cranes must be performed by units qualified for coal mine equipment maintenance.
Coal Preparation Plants & Open-Pit Mines: Dust Explosion-Proof + Anti-Corrosion
Coal preparation plant main buildings carry coal dust explosion risks (Zone 21/22), so cranes must be configured to dust explosion-proof standards. These cranes serve the maintenance and replacement of washing equipment (heavy medium cyclones, flotation machines, vibrating screens, centrifuges, etc.). Open-pit mines use cranes for mining equipment repair and assembly.
Coal Preparation Plant Recommendation: QD type explosion-proof overhead crane (lifting capacity 20–50 t) with Ex tD A21 IP65 dust explosion-proof configuration, or MG type explosion-proof gantry crane (span 22–40 m, with cantilever coverage over the loading area). If the plant operates primarily indoors, an overhead crane is preferred; for mixed indoor/outdoor use, a gantry crane is the better fit. Protection rating IP55 (motor IP55), sealed dustproof electrical enclosure, and C4-grade anti-corrosion coating for outdoor sections.
Open-Pit Mine Recommendation: MG type gantry crane or QD type overhead crane (lifting capacity 32–100 t) for the repair and assembly of mining excavators, crushers, and conveyors. Open-pit cranes operate in high-dust, high-sand outdoor environments and must be equipped with an enclosed cabin with air conditioning, IP55 protection, and C4-grade anti-corrosion coating. For ultra-large tonnage (100 t+), a gantry crane is recommended to reduce rail foundation load requirements.
Mining Equipment Manufacturing & Maintenance Workshops
Cranes in mining equipment manufacturing/maintenance workshops handle the assembly and repair of large mining equipment such as crushers, ball mills, and conveyors. Lifting capacity typically ranges from 16–50 t (the heaviest maintenance item being the crusher mantle/ball mill shell), with spans of 22–31 m and a work duty classification of A5. Configuration essentials: double hook (main hook for large components, auxiliary hook for parts) + variable-frequency speed control + remote control operation. Since welding and gas cutting are performed simultaneously in the workshop, an enclosed cabin (protecting against welding arc flash and dust) is recommended.
If the maintenance workshop has multiple workstations operating simultaneously, a BZD type jib crane (1–3 t) can be retrofitted at each station as auxiliary hoisting equipment to reduce reliance on the main overhead crane. For detailed parameters and selection guidance on mining explosion-proof electric hoists, refer to the related product articles.
Six Core Data Cards for Mine & Coal Cranes: Key Parameters by Application
Frequently Asked Questions (FAQ)
Q: What is the difference between Ex d I and Ex d IIBT4? Can Ex d IIBT4 be used in coal mines?
A: Ex d I is the explosion protection class specifically for coal mine gas environments (methane, explosive range 5–15%, ignition temperature 595°C). Ex d II is for industrial (non-mining) gas environments. The fundamental difference is that Ex d I requires the flameproof enclosure to withstand methane explosion pressure (reference pressure ≥ 1.0 MPa) and must contain no energy-storing components; Ex d IIBT4 enclosures are tested at a lower pressure (approximately 0.8 MPa). Only Ex d I equipment is permitted underground in coal mines — Ex d IIBT4 is not applicable to coal mine underground use; this is a mandatory requirement. Non-coal mines (metal/non-metal) may use Ex d IIBT4 or Ex d II CT4 underground.
Q: Besides the crane's own explosion-proof rating, what special requirements apply to the power supply system in a coal preparation plant?
A: Coal preparation plants are classified as combustible dust environments (Zone 21/22), and the power supply system must comply with GB 50058-2014: ① The crane power supply must be routed from a non-hazardous area, with isolation sealing devices installed where cables enter the danger zone; ② Conductor rails must be of the sealed type (preventing dust ingress that could cause short circuits); ③ The earthing system must use a TN-S configuration (neutral and protective earth conductors separated), with grounding resistance ≤ 4 Ω; ④ Leakage protection must be installed at the main power supply (tripping current ≤ 30 mA); ⑤ Junction boxes within the danger zone must be dustproof (IP6X).
Q: Can a mining explosion-proof electric hoist still be used after its MA certification has expired?
A: No. The MA mining safety mark is a statutory requirement for underground coal mine use — equipment without a valid MA certification must not be used underground (Coal Mine Safety Regulations, Part 4, Article 468). The MA certificate has a validity period of 5 years, and the user unit must initiate the renewal application at least 6 months before expiry. Renewal procedure: contact the original certification body (Mining Safety Mark National Center), submit a statement of equipment changes (whether any retrofit has been carried out), undergo an on-site audit, and obtain re-certification. The MA renewal fee is approximately CNY 10,000–30,000 (about $1,500–$4,500) per model. If the equipment has been retrofitted or discontinued, a new Type Test must be performed.
Q: How do I select an underground crane for non-coal mines (metal/non-metal)?
A: Non-coal mines do not present a gas explosion risk as the primary hazard, but other flammable gases may be present (e.g., hydrogen sulfide in pyrite mines, diesel engine exhaust in copper mines). The explosion protection class for underground cranes in non-coal mines is selected based on the gas group actually present — typically Ex d IIBT4 (e.g., diesel exhaust only) or Ex d IICT4 (where IIC gases such as hydrogen sulfide are present). The key difference is that non-coal mines do not require MA certification but do require CCC Ex certification. The selection logic for underground cranes in non-coal mines is the same as for surface explosion-proof cranes.
