YHJ-200J(A) Intrinsically Safe Mining Laser Distance Meter

Overview

The YHJ-200J(A) Intrinsically Safe Mining Laser Distance Meter is a ruggedized, handheld metrology instrument engineered for precise non-contact distance measurement in hazardous underground coal mine environments. It operates on the time-of-flight (ToF) principle, emitting a Class II visible red laser pulse (635 nm, ≤1 mW) and calculating distance based on the round-trip transit time of the reflected beam. Designed to meet stringent safety requirements for Zone 0/1 mining applications, its intrinsic safety certification (Exib I Mb) ensures no ignition risk from electrical or thermal energy under normal or fault conditions—making it suitable for deployment near methane-air mixtures and combustible dust layers. The device delivers high reproducibility across its full 0.05–200 m range, with a stated accuracy of ±1 mm and 1 mm resolution, enabling reliable dimensional verification of tunnel cross-sections, roof-to-floor heights, pillar spacing, and longwall face geometry.

Key Features

• Intrinsically safe design certified to Exib I Mb standard, compliant with GB 3836.1–2021 and AQ 6201–2019 for coal mine use
• Integrated dual-axis tilt sensor with ±0.3° angular accuracy, supporting real-time inclination compensation during slope-aligned measurements
• Multi-mode measurement suite: single-shot, continuous scanning, area/volume computation, Pythagorean theorem-based indirect distance derivation, min/max tracking, and delayed/offset measurement for hard-to-reach targets
• Backlit high-contrast LCD display with intuitive icon-driven interface, optimized for low-light and dusty underground conditions
• Embedded precision spirit level for horizontal/vertical alignment verification prior to measurement initiation
• Self-calibration routine accessible via menu, ensuring long-term stability of internal reference timing circuits
• Configurable auto-power-off (default 150 s) and laser shutdown timer (20 s) to extend battery life and reduce unintended exposure
• Dual-material housing: ESD-resistant ABS structural body with overmolded TPU grip zones for shock absorption and slip resistance in wet, oily, or icy hand conditions
• IP54-rated enclosure providing protection against limited dust ingress and water splashing from any direction

Sample Compatibility & Compliance

The YHJ-200J(A) is validated for direct measurement on common mine surface materials including sprayed concrete linings, steel mesh supports, timber sets, conveyor structures, and unconsolidated coal faces. Its 635 nm red laser exhibits sufficient reflectivity on matte, non-metallic, and moderately reflective surfaces typical in underground development headings. For highly absorptive (e.g., black rubber conveyor belts) or specularly reflective (e.g., polished rail heads) targets, users may apply standardized retroreflective tape (ISO 20781-compliant) to ensure consistent return signal strength. Regulatory compliance includes mandatory Chinese mining equipment certifications: MA Safety Mark (issued by National Mine Safety Administration), CNEX explosion-proof certification (Certificate No. attached in technical dossier), and third-party type test report per GB/T 13384–2008 (General Technical Conditions for Packing of Measuring Instruments). While not FDA- or EU-CE marked, its intrinsic safety architecture aligns with IEC 60079-11 principles for apparatus protection by intrinsic safety “ib”.

Software & Data Management

This is a standalone field instrument with embedded firmware only—no external software dependency or PC connectivity. All measurement data are stored locally in non-volatile memory (60-record capacity), each entry timestamped and tagged with mode identifier (e.g., “AREA”, “PYTHAGORAS”, “TILT-COMPENSATED”). Records persist through battery replacement and support sequential recall, overwrite cycling, and selective deletion. Audit trails are maintained via internal firmware logging of calibration events and critical error states (e.g., low battery warning, out-of-range tilt, weak signal detection). Although lacking wireless transmission or cloud sync, the unit satisfies GLP-aligned documentation needs for underground survey logs when paired with paper-based field notebooks referencing stored record indices. Firmware updates—when released—are performed via proprietary USB-to-serial adapter and manufacturer-provided utility under controlled workshop conditions.

Applications

• Roof bolting layout verification and inter-bolt spacing validation in development roadways
• Accurate determination of goaf boundary distances during retreat mining operations
• Volume estimation of excavated voids and stockpiled coal using integrated area × height calculation
• Verification of conveyor alignment offsets and drive pulley centerline deviations
• Pre-shift inspection of ventilation duct sag, airway cross-sectional area reduction, and fire door clearance gaps
• Geometric validation of hydraulic support canopy projection and shield advancement increments
• Emergency response mapping: rapid capture of trapped personnel proximity distances and escape route segment lengths

FAQ

Is the YHJ-200J(A) suitable for use in gassy mines with methane concentrations above 1.0%?
Yes—its Exib I Mb marking certifies operation in coal mines where explosive gas atmospheres are likely to occur continuously, intermittently, or occasionally, including environments with methane (CH₄) up to 100% LEL.
Does the device require annual recalibration by an accredited lab?
Per GB/T 16818–2008, field verification using traceable gauge blocks is recommended before each shift; formal recalibration is required every 12 months or after physical impact exceeding 1.5 m drop onto concrete.
Can the tilt sensor be used independently of distance measurement?
Yes—the inclinometer functions as a standalone digital protractor with ±45° range and displays real-time pitch/roll angles on the main screen without initiating laser emission.
What is the expected service life under typical underground usage conditions?
With proper storage (dry, ambient temperature), biannual battery replacement, and avoidance of prolonged condensation exposure, mechanical and optical components maintain specification for ≥5 years of daily operational use.
Is the unit compatible with standard mine surveying datums and coordinate systems?
It does not perform georeferenced positioning; however, measured distances and derived volumes may be manually entered into mine planning software (e.g., Vulcan, Surpac) using local grid references established via total station tie-ins.