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1

Research of Building the Reasonable Mixing Ratio between Waste Rock and Fly Ash as Backfill Material in Mongduong-Cocsau Area, Quang Ninh, Vietnam

Nguyen Phi Hung, Nguyen Cao Khai, Nguyen Thi Kim Thanh

Inżynieria Mineralna

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2023

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no. 2, vol. 1

257--265

EN

The coal mining industry in Quang Ninh province is primarily focused on serving thermal power plants which has resulted in a substantial amount of waste rock and ash. This way has not only narrowed the used land but also had a negative impact on the environment. However, the economic development plan for the province until 2030 emphasizes the development of a greener economy. Therefore, balancing between economic growth and environmental protection is one of the significant challenges of this province. To solve the problem of waste rock and ash dumps, some methods have been proposed. It tends to use waste materials for backfilling the underground mines, this can help to minimize the bad impact on the environment. Additionally, Another solution is to handle the waste in abandoned mining areas, or use them as construction materials. These ways are expected to partially reduce the bad effects of waste rock and ash dumps on the environment. In the world, there are many studies on filling using waste rock and fly ash, but in Vietnam this issue is quite new. In order to turn waste rock and fly ash into filling materials, the article researches on a laboratory scale, the ability of transportation in hydraulic pipelines, level of the water separation and shrinkage of mixtures of rock and fly ash in the Mong Duong – Coc Sau area with the different proportions. The results of the experiments show that the area has appropriate mixing ratio as 70–73% of waste rock and 30–27% of fly ash, this ratio satisfies the transportation conditions in the pipeline and the shrinkage rate of 8, 8–12.3%. The indicators in experiments show that it is able to take waste rock into mined underground area to fill, which prevents displacement of strata from mining, protects the underground water flow, and also reduces negative impact of waste rock on environment.

2

Fracture Mechanism of Hard Main Roof and Determining the Width of Coal Pillars when Extracting Flat-lying Coal Seams

Le Quang Phuc, Dao Van Chi, Nguyen Phi Hung, Vu Thai Tien Dung

Inżynieria Mineralna

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2023

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no. 2, vol. 1

271--280

EN

In underground coal mining, the stability of roadways and gob-side entry depends on the coal pillar width. An unreasonable width of the coal pillar will cause the roadway to be in a dangerous zone of influence of the abutment pressure, leading to severe roadway deformation. This paper studies the fracture mechanism of the hard main roof and reasonable coal pillar width to protect the stability of gob-side entry driving. The research results show that when mining a coal seam under a hard main roof, the console of the main roof on the edge of the coal seam has the form of hinge structure. The great load of the roof layers and the rotation of the console are the main causes leading to the variation of the stress field in the coal seam. According to the development law of the stress field, after the main roof completes the collapse process, the peak of the maximum stress will move deep into the solid coal seam, and on the edge of the coal seam it will form a low-stress zone. Research results from the case of Seam #11 of Khe Cham coal mine, Vietnam show that the gob-side entry will be well stabilized when the narrow coal pillar between it and the boundary of the gob is 4–5 m.

3

Research about building the management for mineral software. Case Study in the Tuyen Quang Province

Nguyen Phi Hung, Bui Manh Tung, Nguyen Caokhai, Nguyen Thi Kim Thanh

Gospodarka Surowcami Mineralnymi

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2022

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T. 38, z. 1

151--169

EN

Mining industry is an important sector that produces materials for other industries, also plays an important role in economic and social development, especially in a developing country like Vietnam. However, mineral mining can destroy the environment and deplete resources over time. The biggest challenge for state managers is to balance the conflict between the mining planning, development planning of other economic sectors and environmental issues. One of the solutions is to replace backward, manual extraction tools with the application of the modern computer (Modernize government administration). In Viet Nam, at present, the provincial management agency of mines faces up with difficult problems such as: backward management method, lowly informative level, not using the current data effectively, even some areas can manage data well but can hardly and lowly share them, the current softwares are mainly document management, most of maps are stored on paper, digital map manage is not really cared. The traditional procedure and technology needs to be innovated by the way of enhancing to synthetically manage mineral resources, this can advance speed and quality of data processing, reduce the burden on employees and raise the level of office automation. The article uses the open code ASP.NET combined with GIS (Geographic Information Systems), based on the mineral economic development planning map in Tuyen Quang province, tools for editing, storing and extracting informaion are built detailedly for activities in mines from the beginning to the end of mining process. As a result, managers and authorities can easily search information for their work.

PL

Przemysł wydobywczy jest ważnym sektorem produkującym surowce dla innych gałęzi przemysłu, odgrywa również ważną rolę w rozwoju gospodarczym i społecznym, zwłaszcza w kraju rozwijającym się, takim jak Wietnam. Jednak wydobycie kopalin może z biegiem czasu niszczyć środowisko przyrodnicze i sczerpywać ich zasoby. Największym wyzwaniem dla dyrektorów spółek państwowych jest zrównoważenie konfliktu między planowaniem górniczym, planowaniem rozwoju innych sektorów gospodarki oraz kwestiami ochrony środowiska. Jednym z rozwiązań jest zastąpienie prymitywnych, ręcznych narzędzi do zarzadzania wydobyciem kopalin przez nowoczesne komputery (modernizacja administracji rządowej). W Wietnamie regionalna agencja zarządzania kopalniami boryka się obecnie z trudnymi problemami, takimi jak: zacofany sposób zarządzania, niski poziom informacyjny czy nieefektywne wykorzystanie aktualnych danych. Obecne oprogramowanie to głównie zarządzanie dokumentami, większość map jest w wersji papierowej, zarządzanie mapami cyfrowymi nie jest tak naprawdę ważne. Tradycyjna procedura i technologia wymagają innowacji poprzez usprawnienie syntetycznego zarządzania zasobami mineralnymi, co może przyspieszyć i poprawić jakość przetwarzania danych, zmniejszyć obciążenie pracowników i podnieść poziom automatyzacji biura. Artykuł wykorzystuje otwarty kod ASP.NET w połączeniu z GIS (Geographic Information Systems), w oparciu o mapę planowania rozwoju gospodarki surowcami mineralnymi w prowincji Tuyen Quang, narzędzia do edycji oraz przechowywania i wydobywania informacji są budowane szczegółowo dla działań w kopalniach od początku do końca procesu wydobycia. Dzięki temu kadra zarządzająca i władze regionalne mogą łatwo wyszukiwać informacje dotyczące swojej pracy.

4

A Solution to Ensure Ventilation when Expanding the Area of Cam Thanh Underground Coal Mine, Ha Long Coal Company, Vietnam

Nguyen Cao Khai, Nguyen Van Tinh, Nguyen Phi Hung, Nguyen Van Quang

Inżynieria Mineralna

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2021

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no. 2

533--542

EN

In the process of underground mining, the mining system changes for various reasons. One of the main reasons is changes in the mining production plans, especially the scales and outputs. Nowadays, coal mines in Vietnam have been expanding in width and depth, and so have the mines’ ventilation systems. Consequently, there will be changes in the alteration of the structure of the design ventilation system, which reduces the effectiveness of the ventilation and does not meet the main objective of mine ventilation, directly affect the safety of the working environment in the mine. Therefore, it is necessary to research the improvement of the ventilation system with the development and specific conditions of underground coal mines in Vietnam, improving the efficiency of the ventilation work and assuring the safety of the mine environment. Cam Thanh coal mine, Ha Long coal company, Vietnam, is the case study for this research. The article considers the plan of increases the mining output by more than 1.5 times, propose solutions to improve the ventilation system accordingly, helping the company proactively implement the production plan, ensure the working environment's safety, and reduce the costs of mine ventilation.

5

Front Stress Distribution Under the Impact of Cutting Height to Caving Height Ratio in Extra-thick Longwall Top Coal Caving Technology

Bui Manh Tung, Nguyen VanQuang, Nguyen Phi Hung, Vo Ngoc Dung, Do Hoang Hiep

Inżynieria Mineralna

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2020

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no. 2, vol. 1

123--129

EN

The extraction with higher cutting height for extra-thick seam is the new research orientation in longwall caving technology. Due to the increase of top coal thickness and of cutting height which leads to the change of cutting/caving height ratio, the rule of roof failure (including top coal caving) and the distribution of stress around the face alter correspondingly. This paper is based on the geological conditions of face 8102 of Tashan-DaTong mine, employing the numerical model by UDEC2D code, analysing the effect of cutting/ caving height ratio on the law of stress distribution ahead of the face. When the ratio of cutting/caving height decreases and the cutting height increases, the results of the research have shown that: (i)- peak stress redistributes further ahead of the face and its value manifestly drops; (ii)- the plastic deformation ahead of face significant increases and the zone of plastic strain also expands. It is therefore concluded that the variation of cutting/caving height ratio results in the redistribution of roof pressure, which contributes to the control of roof failure and face stability.

PL

Przy bardzo grubych pokładach, eksploatacja z dużą wysokością to nowy kierunek badań w technologii zawału stropu węgla. Ze względu na grubość warstwy stropu węglowego i zwiększoną wysokość urabiania prowadzi do zmiany stosunku urabiania do odzyskania, co również zmienia regułę zapalenia skał stropowych i zmienia stan rozkładu naprężeń wokół ściany. W artykule, przedstawiono wyniki analizy wpływu stosunku urabiania do uzyskania opierając się na prawie rozkładu obciążenia przed ścianą. Analiza ta została oparta na warunkach geologicznych kopalni 8102 TaSan-DaTong wykorzystując model numeryczny UDEC2D. Wyniki badań pokazują, że wraz ze spadkiem stosunku urabiania do odzyskania, oznacza to wzrost wysokości urabiania, położenie maksymalnego naprężenia jest daleko od ściany, maksymalna wartość naprężeń znacznie spada, zniszczenie plastyczne przed ścianą i stropem gwałtownie rośnie, zwiększa się strefa odkształcenia plastycznego. Dlatego zmiana stosunku urabiania do odzyskania może zmienić stan rozkładu ciśnienia stropowego, co jest korzystne dla procesu niszczenia stropu i kontrolowania stabilności ściany.

6

Current Situation and Solutions to Advanced Ventilation Efficiency in Giap Khau Coal Mine Area, Hon Gai Coal Company of Viet Nam

Nguyen Cao Khai, Nguyen VanThinh, Nguyen Phi Hung, Dao Van Chi, Nguyen Van Quang

Inżynieria Mineralna

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2020

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no. 2, vol. 1

209--219

EN

Mine ventilation aims to dilute toxic gas concentrations, dilute dust concentrations, remove them from the mine and ensure pleasant microclimate conditions in the mine, especially at work sites. Currently, in underground coal mines in general and in Giap Khau mine area, Hon Gai coal company, in particular, is in the process of converting the mining area into deep, as well as increasing output. Therefore, it is important to ensure that ventilation is a top priority in long-term occupational safety and meets the plan to increase coal production. In this study, we have evaluated the current state of ventilation in Giap Khau mine area. From those research results, on the basis of computational research methods, we have come up with reasonable solutions to change and improve ventilation efficiency for the mine in the condition of complicated mining plan and technology characteristics are still limited compared to those in the world. Specific solutions solve 2 problems: First, ensure ventilation for the current mining operation stage; Secondly, we have researched and proposing suitable solutions for ventilation of Giap Khau area mine when it has to increase production and move down to an adjacent project at a deeper level.

PL

Zwiększająca się głębokość pokładów węgla w kopalniach podziemnych ogólnie mówiąc a szczególnie w kopalni Giap Khau i związany z nią wzrost temperatury pierwotnej górotworu są powodem pogarszania się warunków mikro-klimatycznych pracy górników i wystąpienia zagrożenia klimatycznego w przodkach górniczych. Wentylacja ma na celu rozrzedzenie stężeń gazów toksycznych, rozrzedzenie stężeń pyłów, usunięcie ich z kopalni oraz zapewnienie przyjemnych warunków mikroklimatycznych. W artykule, przedstawiono wyniki oceny aktualnego stanu wentylacji w kopalni Giap Khau i odpowiednie rozwiązania, które pozwalają poprawić efektywność systemu wentylacji zwalczając zagrożenie klimatycznych kopalni.