Client Background

Fresnillo silver mine is located in the state of Zacatecas, Mexico. It is one of the world's oldest and largest primary silver producers, with nearly 500 years of continuous operation. The mine produces silver and gold as primary products, with lead and zinc as by-products. Underground deep-shaft mechanized mining methods are employed, featuring significant ore body depth and extensive tunnel development work. Ground support is a critical process for ensuring mining safety. DICOM, the mine's main contractor, is responsible for comprehensive works including drilling and blasting, ground support, mucking, and infrastructure installation.

Challenges Faced

Ground Support Efficiency Bottleneck: The mine previously used dry shotcrete for tunnel support. The process suffered from high rebound rates and severe material waste. Single-pass application thickness was limited, requiring multiple re-spray passes to achieve design strength, which severely constrained tunnel advance rates.

Working Environment and Safety: The dry shotcrete process generated excessive dust, posing high occupational health risks to miners. Operators were required to work in close proximity to the nozzle, facing dual risks of face fallouts and rebound material injuries.

Long Transport Distances: The concrete batching plant was located on the surface, with underground working faces up to 10 kilometers from the shaft. Long-distance transport of wet-mix concrete placed stringent demands on material workability retention and equipment adaptability.

Beijun Solution

Shandong Beijun Group provided a customized mechanized ground support solution centered on wet shotcrete machines, tailored to the deep-shaft, long-distance transport, and high-ground-support requirements of Fresnillo silver mine:

Primary Shotcrete Equipment: Beijun Intelligent Wet Shotcrete Jumbo (Mining Grade)
   Equipped with a specialized concrete pumping system, theoretical spraying efficiency reaches 20m³/h. Supports dual-power drive (electric motor / diesel engine) to adapt to different underground power supply conditions. The unit features a remote control operating system, allowing operators to work away from the face, fundamentally eliminating safety hazards associated with close-range handheld nozzle operation.

Supporting Equipment: Beijun Underground Concrete Transport Truck
   Designed for long-distance transport requirements, the unit is equipped with a specialized concrete mixing and agitating device that effectively controls slump loss during transport. This ensures that concrete maintains good pumpability and spraying quality upon arrival at the working face, forming a complete "batching-transport-spraying" operational chain with the wet shotcrete jumbo.

Precision Additive Dosing System:
   Equipped with an automatic accelerator metering and dosing device that adjusts additive dosage in real-time proportion to concrete flow rate. This ensures consistent shotcrete layer thickness and quality, reducing material rebound rate to under 10 percent.

Implementation Results

Ground Support Efficiency Significantly Improved: The mechanized wet shotcrete process achieves single-pass application thickness of over 15cm, reducing re-spray frequency. Single-cycle support time is reduced by approximately 40 percent compared to the dry shotcrete process, significantly accelerating tunnel development cycles.

Working Environment Significantly Improved: Dust concentration from the wet shotcrete process is reduced by over 90 percent compared to dry shotcrete. The underground working environment has been substantially improved, and miner occupational health is effectively protected.

Material Rebound Rate Substantially Reduced: Dry shotcrete typically has a rebound rate of over 30 percent. After adopting Beijun's wet shotcrete equipment with precision additive control, rebound rate dropped to under 10 percent, significantly reducing material waste and overall ground support costs.

Safety Risks Effectively Mitigated: Remote control operation achieves man-machine separation, keeping operators away from the spraying face. This eliminates accidents caused by face fallouts and rebound material injuries, achieving the safety goals of "mechanization replacing manpower and automation reducing personnel."

Client Testimonial

"Beijun's wet shotcrete units have brought systematic change to our underground ground support operations. The transition from dry to wet shotcrete is not just an efficiency improvement – it is a fundamental safeguard for miner safety and health. The equipment is easy to operate; our local miners can operate it proficiently after training. We plan to promote Beijun's wet shotcrete equipment to more working faces in the future."