Like all member units of the Vietnam National Coal - Mineral Industries Group in the Quang Ninh region, Nui Beo Coal Joint Stock Company was severely affected by storm No. 3. Although it quickly consolidated the factory, started production, and released coal right after the storm, Nui Beo Coal still encountered many geological difficulties.
Storm No. 3 caused the entire power supply, water supply, steam supply, and compressed air supply system for all production locations of Than Nui Beo to be "paralyzed" for nearly a week. The operator's house and the shelter of the main fan station collapsed, causing wet equipment and damaged inverter cabinets. Many architectural works and conveyor systems outside the premises were blown down by the storm, with roofs blown off, glass broken, ceilings collapsed... Under the furnace, some tunnels were flooded by water flowing in from the furnace door, carrying rocks, causing local flooding in many locations.
Notably, the power grid was cut off for about a week, causing the two main and auxiliary vertical shaft loading systems of Nui Beo Coal to stop operating. These are two particularly important projects for Nui Beo Coal's transportation work, with the task of transporting all soil, rock, raw coal, labor and equipment up and down the mine to serve production.
Mr. Tran Quoc Tuan, Deputy Director of Nui Beo Coal Joint Stock Company - Vinacomin said: The entire shaft operation building, the main well tower cover house and the auxiliary well tower, and the round optical system operation house had their roofs blown off in storm No. 3. The rainwater flooded down at the same time as the power grid was cut off, causing the transportation activities of Nui Beo Coal Joint Stock Company to be suspended for a week.
In an urgent manner, the unit quickly organized the installation of the corrugated iron roof of the well mouth cover and the house containing the two well loading shaft equipment; assessed the technical condition of the entire equipment system and combined the calibration test of the loading shaft equipment of both the main and auxiliary vertical wells. From September 11, 2024, the unit's production lines returned to normal operation. 10 days after stable operation, Than Nui Beo produced over 33,000 tons of coal and dug more than 330 meters of tunnel.
Mr. Doan Dac Tho, Party Secretary and Director of the Company, affirmed: Storm No. 3 has passed and the severe consequences caused by natural disasters have been overcome. We have released coal as soon as possible in the safest conditions. The pumping pit and power station - the heart of the mine - have been preserved. All production lines and essential equipment have been quickly restarted right after the storm. It can be said that the efforts of a collective with a rich tradition of discipline and unity have been duly rewarded. In the midst of difficulties, the leadership team and workers of Nui Beo Coal have stood side by side, working together to rapidly restore the mine's production system to keep the coal flowing.
"However, Nui Beo has never been without difficulties. The mineral deposits with many rocks and clamps are a "specialty" of this mine. The quality of raw coal is affected by the relatively complex folding faults in many areas during the mining process. In addition, in the seam, there are additional sandwich layers with components of coal clay and clay aggregate, which increase the ash content (Ak). In addition, the mechanized furnace encountered high water pressure during the transfer process, affecting the mining output," the director added.
To solve difficult geological problems, Nui Beo Coal has proactively identified and developed effective construction measures. The Company is always one step ahead in exploration work, zoning areas at risk of faults and having a plan to bypass to minimize rock cutting. To ensure resource savings and coal quality, the work of separating and filtering rocks right at the furnace mirror before transporting them to the ground is always focused on. In addition, for mining areas facing high mine pressure conditions, the Company focuses on measures to adjust the appropriate support structure, organize anti-lifting, lower the foundation, trim and repair the tunnel... to ensure safety.
According to the 2024 plan, Nui Beo Coal Joint Stock Company will carry out tunnel excavation and exploitation of the CGH 21108 longwall; Gia Xich 21117 longwall, Gia Xich 41009 longwall and Gia Xich 30703 longwall. During the process of tunnel excavation of the longwalls, the geological conditions are basically stable, ensuring the technical conditions to put the longwalls into operation as planned.
However, the exploitation of the above longwalls encountered changing geological conditions, which were different from the original design documents, and encountered unexpected faults in the middle of the longwalls, which forced the longwalls to drill and blast a part of the rock in the area adjacent to the fault, thus affecting the quality of the mined coal.
When an unexpected fault occurred in the middle of the furnace, causing the furnace to have to cut off part of the rock in the area adjacent to the fault, the Company proactively implemented many solutions to fix it.
According to Mr. Nguyen Van Dinh, Head of Mining Engineering and Technology Department, the Company has organized a reasonable mining cycle, flexibly adjusting the coal and rock transportation time to separate coal when cutting the longwalls. At the same time, the Company has also maximized the flexibility of the chained longwall support structure to change the support slope angle (raising and lowering the foundation) to ensure maximum reduction in rock cutting volume and maximum exploitation of resources.
When encountering a large amplitude mid-market fault, divide the market furnace into two parts (lifting wing and lowering wing) and actively separate the transport route in two directions: transport vertical furnace and ventilation vertical furnace to suit the parameters of the transport equipment in the market furnace.
To determine the amplitude of the fault and the morphology of the fluctuating conditions, the Company conducts exploratory drilling with medium and long-range drills in the mine; at the same time, it checks and determines the coal seam ahead according to the discount method to promptly propose a reasonable mining plan and technology, in order to maximize the quality of raw coal and maximize the exploitation of resources.
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