TBM (hard rock tunnel boring machine), as a super equipment for underground engineering construction, can not only cut through mountains and crush rocks in tunnels, divert water and build roads, but also cut coal and break rock in mines, open up roadways, and allow coal, known as "black gold", to emerge from the ground. In this issue of "Special Forces in Action" Part 12: Efficient Tunneling with Mining TBM Boosts Safe Coal Mining, let us focus on the Gaojiabao Mine of Zhengtong Coal Industry and pay attention to the story of CRCHI's mining TBM efficiently assisting coal mining.

The Gaojiabao Mine of Zhengtong Coal Industry is the second modern large-scale mine developed and constructed by Shandong Energy Zibo Mining Group in the Binchang Mining Area of Shaanxi Province. It is located in the northwest of the Binchang Mining Area, one of the 13 large coal bases planned by the state. The mine covers an area of 560 mu, with a mine field area of 219 square kilometers, geological reserves of 970 million tons, designed recoverable reserves of 470 million tons, and a designed production capacity of 5 million tons per year.

CRCHI's third-generation new open-type TBM DZ909

In the parallel drainage roadway project of the Gaojiabao Mine, CRCHI's third-generation new open-type TBM DZ909 achieved a cumulative tunneling of 330 meters in the first month, with an average daily advance of 11 meters and a maximum daily advance of 15.5 meters. DZ909 absorbed the design experience accumulated from the previous two generations of mining TBMs. To cope with the characteristics of weak surrounding rock in coal mines, the whole machine was shortened to 45 meters, adapting to the tunneling of mining roadways with large slopes and small turns.

From the assembly of the first shield body in the factory to the joint debugging of the whole machine, and then to the last box of spare bolts for disassembly and delivery, from project management, research and development, production, delivery to installation, all departments of CRCHI responded actively, formulated detailed node plans, reasonably arranged personnel and cooperated closely to complete equipment assembly with quality and quantity guaranteed.

Cutterhead lowering into the shaft

The TBM in this project was lowered into the mine via a vertical shaft cage at a depth of about 800 meters. After the cage reached the bottom, long-distance roadway transportation was still required. There were many transportation methods and complex transfers, posing a huge challenge to the on-site advance planning of transportation routes. Before the equipment arrived at the site, the on-site service personnel had made sufficient preparations, working 24-hour shifts for unloading, loading, transfer, lowering into the shaft, underground transfer, underground turning, and transport to the assembly cavern, using an assembly line method to complete various shaft entry tasks.

The assembly cavern is at a buried depth of 947 meters. The underground temperature is relatively high, and the ventilation conditions at the assembly cavern are poor. Facing various unfavorable external conditions, the on-site service personnel overcame the adverse on-site environment, worked day and night, and communicated closely with the customer, shortening the on-site assembly time from the normal 25 days to 17 days, and the debugging and launching time from 15 days to 7 days.

Equipment tunneling

The early accumulation laid a strong foundation for the outbreak after launch. The equipment took advantage of the momentum to tunnel, and the daily advance continued to break through. At present, the daily advance is stable at more than 12 meters, challenging the excellent result of 360 meters per month. The progress is more than three times that of traditional coal mine roadway development, greatly solving the problem of imbalance between coal mining and excavation, and gaining customer recognition.