Precautions for Diesel Generator Sets Used in Mines

Diesel generator sets are critical power equipment in mines, especially in areas without grid coverage or with unreliable power. Their operating environment is harsh and demands extremely high reliability. Below are the key precautions for the selection, installation, operation, and maintenance of diesel generator sets in mining applications, divided into core sections.

I. Selection and Design Phase: Mitigating Risks from the Source

This is the most critical step. Incorrect selection will lead to ongoing problems.

1. Power Matching and Redundancy:

Adequate Margin: Mining equipment often consists of high-power motors (e.g., crushers, ball mills, hoists) with very high starting currents (5-7 times the rated current). The generator set’s rated power must be at least 1.5 times the total power of all simultaneous operating equipment and must withstand the starting surge of the largest single piece of equipment. It is advisable to select a set rated for Standby Power rather than Prime Power.

Consider Power Factor: Mining equipment has high inductive loads and a low power factor (typically 0.7-0.8), meaning the required apparent power (kVA) is greater than the active power (kW). Sizing must be based on kVA.

2. Environmental Adaptability:

Altitude and Derating: Mines are often located at high altitudes. Altitude reduces engine power (generally, power decreases by about 10% for every 1000 meters above sea level). The mine’s altitude must be specified, and the manufacturer must provide a high-altitude model or apply appropriate power derating.

Explosion-Proof Design: For mines with risks of explosive gases like methane or coal dust (e.g., coal mines, underground operations), it is mandatory to use mining-approved explosion-proof diesel generator sets. Their exhaust systems, electrical components, starter batteries, etc., require special explosion-proof treatment.

Protection Rating: The enclosure should have a minimum protection rating of IP23 to prevent dust and water splashes. For extremely dusty environments, a higher rating (e.g., IP54) or additional dust protection housings should be considered.

3. Ancillary Equipment:

Heavy-Duty Radiator: Mine dust can easily clog radiators. A larger, heavy-duty radiator that is easy to clean, equipped with a dust screen, is essential.

High-Performance Air Filter: Must use two-stage or multi-stage dry-type air filters (e.g., with primary and secondary filters) equipped with a vacuum indicator to signal when to replace the filter element.

Fuel Pre-Filter/Water Separator: Due to often poor fuel quality, a large fuel-water separator and pre-filter unit must be installed before the engine’s own filters, with regular water drainage.

II. Installation and Commissioning Phase: Laying the Foundation

1. Installation Location:

Adequate Ventilation: Ensure air intake and exhaust outlets are unobstructed and away from dust sources. The room design must provide sufficient fresh air.

Solid Foundation: Pour a solid concrete foundation, securely anchor the set with anchor bolts, and use vibration dampers to withstand operational vibrations and nearby blasting shocks.

Away from Hazard Zones: Avoid areas prone to geological hazards like landslides, collapses, or flooding, and keep a safe distance from blasting sites.

2. Cable Connection:

Use cables with sufficient cross-sectional area and ensure connections are tight to avoid heating due to high contact resistance.

Cables should be laid properly to prevent crushing or abrasion.

3. Commissioning:

Must be performed by professional technicians. Carefully check all parameters (voltage, frequency, waveform, phase sequence) for correctness.

Perform load bank testing, ideally simulating real-world maximum and impact loads to verify performance.

III. Operation and Usage Phase: Procedures Ensure Safety

1. Fuel Management:

Fuel Quality: Use standard,legitimate) diesel fuel that meets national standards. Avoid inferior fuel. Use the appropriate grade for high-altitude areas (e.g., -10#, -20#, or even -35#).

Fuel Storage: Storage tanks must be clean and sealed. Drain water and sediment regularly to prevent contaminants and water from entering the fuel system.

2. Cooling System:

Coolant: Use qualified antifreeze/corrosion inhibitor coolant, not plain water.

Radiator Cleaning: Daily, after shutdown, the radiator fins and dust screens must be cleaned using compressed air or steam. This is one of the most crucial daily maintenance tasks in a mining environment.

3. Air Intake System:

Air Filter Check: Check the air filter restriction indicator every shift. Clean or replace the element immediately if the indicator warns. When cleaning, never use compressed air from the inside out; always blow from the outside in.

4. Standardized Operation:

Operators must be trained.

Perform pre-start checks (engine oil, coolant, fuel, battery electrolyte, leaks).

Never start or stop the engine under load.

Never refuel while the unit is running.

Monitor instrument panel data (oil pressure, water temperature, voltage, frequency) for normal readings.

IV. Maintenance and Upkeep Phase: Key to Longevity

Maintenance intervals in mining environments should be shortened compared to standard recommendations.

1. Shorten Maintenance Intervals: Due to dust and heavy loading, change engine oil, oil filters, fuel filters, and air filters 20%-30% more frequently than the manufacturer’s standard recommendations.
2. Routine Maintenance: Establish a strict inspection system, including checks on the “three filters” (air, fuel, oil), fastener tightness, belt tension, etc.
3. Long-Term Storage: If the set will be idle for a long time, it must be properly preserved (e.g., adding preservative oil, draining coolant, periodic barring).
4. Spare Parts Inventory: Given the remote location of mines, maintain an inventory of common wear parts and critical spares (filters, belts, sensors) to minimize downtime.

V. Safety Precautions

1. Fire Prevention: Prohibit open flames near the generator set. Equip with sufficient fire extinguishers (CO2 or dry powder).
2. Burn Prevention: Exhaust pipes, mufflers, and radiators are extremely hot during operation. Install guards and warning signs.
3. Hearing Protection: Operators must wear hearing protection.
4. Electrical Safety: All electrical work must be performed by qualified electricians following strict safety procedures (lockout-tagout, verification, grounding).
5. Underground Explosion-Proofing: For underground explosion-proof units, any repair or modification must be performed by certified personnel according to explosion-proof standards. Unauthorized alterations are strictly prohibited.

Summary:

The core principles for managing diesel generator sets in mines are: “Careful Selection, Robust Foundation, Strict Operation, and Diligent Maintenance.” Treat them as the lifeline of mining production. Through meticulous management to combat the harsh environment, you can ensure their reliable, efficient, and long-lasting operation, providing uninterrupted power for safe mine operations.

If you have any questions about diesel generator sets, you can always contact MAMO Power!

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