Study on technological solutions and management for sustainable developments of building stone mines in vietnam

MINISTRY OF EDUCATION AND TRAINING UNIVERSITY OF MINING AND GEOLOGY HOANG CAO PHUONG STUDY ON TECHNOLOGICAL SOLUTIONS AND MANAGEMENT FOR SUSTAINABLE DEVELOPMENTS OF BUILDING STONE MINE

MINISTRY OF EDUCATION AND TRAINING

UNIVERSITY OF MINING AND GEOLOGY

HOANG CAO PHUONG

STUDY ON TECHNOLOGICAL SOLUTIONS AND MANAGEMENT FOR SUSTAINABLE DEVELOPMENTS OF BUILDING STONE MINES

The thesis is completed at:

Department of open pit mining, Faculty of mine,

University of Mining and Geology

Scientific supervisors:

1 Prof Dr Tran Manh Xuan

Vietnam Mining Science and Technology Association

2 Dr Nguyen Phu Vu

Vietnam Mining Science and Technology Association

Reviewer 1: Prof Dr Nhu Van Bach

Vietnam Blasting Engineering Association

Reviewer 2: Ass Prof Dr Bui Xuan Nam

University of Mining and Geology

Reviewer 3: Dr Lai Hong Thanh

General Department of Geology and Mineral of Vietnam

The doctoral dissertation defense will be made before the Thesis Examiner Council of the University of Mining and Geology, Duc Thang Ward - North Tu Liem District - Hanoi

At date month year 2016

The thesis can be referred at:

- National Library, Hanoi;

- Library of University of Mining and Geology

Minerals used for construction vary widely, including rock, sand and soil; among these, building stone have the highest proportion in both quantities of mines, output, value as well as the amount of workforce involved in the production stage Exploitation scales of the mines, especially stone mines, are also varied, ranging from tens of thousands to millions of cubic meters per year Exploitation technologies applied may be manual, semi-mechanized, fully mechanized at different levels

This industry has provided construction materials for economic development of the country It creates jobs for thousands of workers and significantly contributes to the national budget However, it also has many drawbacks associating with security, rational use of resources and environmental protection Reasons for these drawbacks include outdated mining techniques, especially in quarrying and insufficient licensing in some localities Therefore, the research is necessary and can contribute to the sustainable development of the mining sector for construction materials of the country

2 The purpose of the study

- The research proposes solutions in stone mining for construction materials to improve production efficiency, safety, environmental protection and resource recovery Based on classification of mines according to terrain conditions and sizes, the research studies the ability to apply the suitable system

of exploitation (SE)

- The research proposes solutions to improve management, specifically about mining licensing, mine networks under planning; encourage the mining sector for construction materials to apply advanced techniques to enhance production efficiency

3 Object and scope of the research

- Stone mines for conventional construction materials and for cement production

- Particularly in the section of technological solutions, the research is only focused on the mines locating above the level of gravity drainage

4 Subject’s matters

- Overview of the exploitation and management of stone mining in the country as well as experience in the world

- Classification of mines by the terrain conditions and sizes Classification

of SE of the mines by features that match the mining technology; analysis of applicability and conditions

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- Construction of technological schemes, calculation of parameters for SE, orders of exploitation, the capability between opening and exploitation for each type of classified mine

- Establish criteria for mining licensing mechanism and innovative solutions for technical management and mine administration

5 The scientific and practical significance

- Scientific significance: improving the theory of open-pit mining for stone mines in complex and fragmented terrain conditions where various technologies need to be applied within the same mine; improving mining licensing model and management of stone mines

- Practical significance: the research serves as the scientific basis for state management agencies and enterprises to refer and apply comprehensive technology and management, to facilitate the stone mining sector to apply advanced technology into production; to ensure safety and rational use of mineral resources as well as environmental protection

6 Arguments

- The selection of appropriate mining technologies or application of technical solutions must take into account the type of mine classified based on terrain conditions and mine size The SE classification also needs to add more details about the characteristics of the production stages on mine

- Management must rely on scientific-based economical and technical criteria and current operations as well as the development trend in the future

- The improvement of mining technologies as well as the innovation of management mechanism to encourage enterprises to apply advanced mining techniques for production efficiency, safety and environmental protection is the precedence for a sustainable stone mining sector

7 Innovative aspects of the thesis

- Propose a mine classification method according to terrain conditions and mine size, classify stone mining SE as a basis for the selection of mining technologies or improving appropriate exploitation techniques

- Propose a calculation method for parameters of SE, method of benches preparation, mining order when various techniques are applied

- Propose scientific-based criteria for licensing; manage stone mining sector based on planning, merge adjacent small mines into larger mines to enhance financial capability for more advanced technology; build self-governance regulations based on the "Self-test" sheet

8 Layout of the thesis

Besides the introduction and conclusion, the thesis consists of more than

150 pages, numerous tables and figures and references from Vietnam and other countries:

Chapter 1 Overview of mining technology and the management of building stone mines in Vietnam and experience of stone mining in the world

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Chapter 2 Analysis of the factors affecting the sustainable development

of building stone mining in Vietnam

Chapter 3 Research on the technological solutions to ensure the sustainable development of building stone mining in Vietnam

Chapter 4 Research on management solutions to ensure the sustainable development of building stone mining in Vietnam

9 Publications

According to the research direction, 14 papers and/or abstracts have been published in magazines of mining, domestic and foreign conferences

CHAPTER 1 OVERVIEW OF MINING TECHNOLOGY AND MANAGEMENT OF BUILDING STONE MINES IN VIETNAM AND

EXPERIENCE OF BUILDING STONE MINING IN THE WORLD

1.1 Overview of potential and distribution of building stone in Vietnam

Vietnam possesses abundant sources of rocks for construction materials across the country According to incomplete statistics, reserve of cement

limestone in Vietnam is about 44.7 billion tons and reserve of rocks for

conventional construction materials is about 53.6 billion tons (Table 1.1)

Table 1.1 Building stone reserves in Vietnam

Red river delta

North Central Coast, Central Coast

Central Highlands

South East

Mekong Delta Total

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1.2 The situation of production and consumption of stone

The abundant stone resource has met the raw material demand for cement production with increasing output: 67 million tons in 2010, 72 million tons in

2014, and expected 112 million tons by 2020 The output for building stone reached 110 million cubic meters in 2010, 115 million cubic meters in 2014 and

is expected to reach 226 million cubic meters by 2020 (Table 1.4)

Table 1.4 Statistics and forecasts of demand for building stone and cement stone

1.3 Overview of the mining technology of building stone mines in Vietnam

Currently, there are 351 mines for cement production, 564 mines for conventional construction There are various technology applications being applied and can be grouped into 4 following categories:

1.3.1 Mining in vertical slicing, conveying by blasting (non-standard mining

or free mining)

This is a non-leveling, non-standard mining method, which used drilling and blasting to remove rock from the blocks on the inclined plane to toe of slope This technology is applied mainly for conventional building stone mining and small scaled cements stone mining The method is currently applied for many mines in the North including Ninh Binh, Ha Nam, Hai Duong, Hai Phong, Thai Nguyen, Lang Son, etc The hammer small-diameter drill ( = 32 - 45mm), shoveling by bucket excavator with a capacity E ≤ 0.5m3 and truck with load of 5-7 tons are applied in most of the mines

Advantage: This is a simple mining technology, low investment, cheap cost and suitable for small-scale mining companies with limited financial conditions; the requirement for mining area is not large

Disadvantage: This mining technology is an unsafe; causes wasteful and loosed resources; potentially high environmental pollution and easily leading to the situation of only mining the easy parts while giving up the difficult ones

1.3.2 Mining in horizontal leveling and conveying by truck

This technology is applied mainly to limestone mining for cement production

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This technology is mainly applied to stone mining of the lower part of the mountain after initial top cut: Yen Duyen (Thanh Hoa), Ang Dau, Ang Son (Hai Duong), etc mines The mining equipments using in these mines are very diversity, of which the drill rig with drilling diameter of  = 105 - 200mm, bucket excavator with capacity of bucket E = 1.2 - 1,8m3, truck with load of 10-

15 tons and height of slice h = 10 - 15m are very popular

Advantage: High mechanized ability; safe operation, can exploit

selectively, low environmental pollution

Disadvantage: Great investment capital, long time of mine preparing, expensive cost

1.3.3 Mining in vertical slicing and conveying by bucket excavator and truck

This technology is applied for some following mines: Thong Nhat (Hai Duong), Hoa Thach Lien (Hanoi), Dong Tram Hoa (Ha Nam), Tien Hoa (Quang Binh), etc The mining equipments included drill rig with drilling diameter of  = 105mm, bulldozer with capacity of 130 - 240CV, excavator with bucket capacity of E = 0.8 - 1,6m3 and truck with load of 15 tons are used The height of slice is less than 7 meters; the cut width is less 10 meters

Advantage: This is a simple mining operation technology, which can be applied for Stone Mountain with heavy pitch

Disvantage: The application is restricted in case of large volumes, requires large, long working platform, causes huge amount of dust during shoveling and transporting stone to mountainside or pit slope

1.3.4 Mixed mining technology

This technology is as follows: The upper part of the mountain is mined in horizontal slicing using hydraulic drill rig with drilling diameter of 64 - 130mm and shoveled by bucket excavator with capacity of E = 4-6m3, or using bulldozer with capacity of 130 - 420CV The stones are shoveled from working platform at the toe slope using bucket excavator with capacity of E = 3.5 - 4,6m3 and transported by truck with loading capacity of 27-40 tons The lower part of the mountain is mined in horizontal slicing, and then transported by truck

This mining technology is applied quite popularly in some mines: Trang Kenh (Hai Phong), Minh Tan (Hai Duong), But Son, Hong Son (Ha Nam), Yen Duyen (Thanh Hoa), Hang Nuoc (Ninh Binh), Hoang Mai A mine (Thanh Hoa), etc

Advantage: Capable of full mechanization of production in mines, can increase yields while exploiting the lower and selective, safe shoveling

Disadvantage: complex mining operation, causing huge amount of dust during shoveling or shifting

1.4 Some experience in building stone exploitation in foreign countries

As with Vietnam, other countries must counter difficulty in mines in mountainous areas due to the complex terrain and it is impossible or too expensive to make trenches from the ground up to the mining slices for

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transportation of stone Therefore, stone transportation using gravity combined with other forms is applied to reduce the distance and costs during exploitation Accordingly, seams may be opened by wells or pits, taking advantage of gravity

to transport rocks down from the height

It is shown from foreign literatures that seam opening of the working slices

in underground mining for transportation by gravity is reasonable if the slope is greater than 200 Wells can be used to transport rocks in open pit mines with output of 4-5 million tons/year, while the use of chutes achieves lower output

In addition to plans for "hopper – vertical shaft and transport by narrow rail haulage in tunnel mining" was applied in the early stages, today many countries apply a relatively modern exploitation technology combining "gravity

- conveyor" with crusher located at the bottom of the well (the UK, Australia, Japan, Switzerland, etc.)

This technology is applied in mines that operate in vertical slicing with car or loading machine as transportation vehicles and height of bench is usually 15m Devices are synchronized and advanced: hydraulic drill with diameters from 80 - 203mm, loading machine with bucket capacity of 5 - 20m3, excavator with bucket capacity of 5 - 7,5m3, and truck with load of 40-80 tons

Mining technology with stones being conveyed by bulldozers on horizontal or inclined surface is also applied in several mines in Spain, Germany and Algeria

1.5 The current status of the management of the building stone mines

1.5.1 Current status of mine licensing and land leasing, and some issues

Mine licensing and land leasing for mining in Vietnam can be described

by the following diagram (Figure 1.9):

Figure 1.9 Mine licensing and land leasing model

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In some localities, mine licensing still has the nature of “asking and giving”, is not scientific and practical based, creating red tapes for the enterprises, leading to fragmentation, unsafe mining, overlapping, waste of resources and environmental destruction There has been lack of consensus between mining licensing bodies and land leasing agencies

1.5.2 Inspection

In recent times, the inspection work lacks the coordination between central and local agencies; the inspection work is still considered largely an administrative task

1.6 Analysis of the related studies

There have not been many studies in technology of building stone mining

in our country The vice doctoral thesis of Nguyen Thanh Tuan (1985) is among the best known work in this field There are also 02 technical master thesis of

Le Thi Thu Hoa (1998) and Nguyen Minh Huan (1999) Besides, there are some other studies for curriculum or reference books by such authors as Tran Manh Xuan, Ho Si Giao, Bui Xuan Nam, etc

The previous studies have not suggested the appropriate technological scheme for stone mining in different terrain conditions and sizes or analysis of application field for each type of ES; there is no research on improving the state management on the stone mining for construction materials

CONCLUSION OF CHAPTER

Currently in Vietnam, most mines use outdated technology, especially small-scaled mines and stone mines for conventional construction materials The outdated technology applications lead to waste of resources, environmental destruction, pollution and low economic efficiency

The main reason is that suitable technology applications are yet to be found Management of mining operations is inadequate

CHAPTER II ANALYSIS OF FACTORS AFFECTING THE SUSTAINABLE

DEVELOPMENT OF BUILDING STONE MINING IN VIETNAM

2.1 Management factor

2.1.1 Mine licensing

An efficient open-pit stone mine needs 02 following conditions:

- Proper area for normal operation,

- Life span of mine longer than payback time

If mine licensing is only based on the reserve and exploitation duration without the consideration of the area of mine, the application of technology for efficient operation is difficult

2.1.2 Method of reserve calculation to pay for mining rights

Mineral reserve used as a basis to pay for the mining rights is calculated

by vertical section and depth of mine floor, which leads to the difference

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between calculated reserve as regulated and the actual reserve due to the presence of mine banks This causes economic losses for mining enterprises, and the extent of loss depends on the depth and angle of the bank

In addition, the application of the same expansion coefficient for all mines is not rational

2.1.3 Inspection

There lacks of coordination among agencies regarding inspection of mines, and the reporting and information management is still inefficient A system of specialized inspection agencies from central to local has not been formed, which leads to the inefficient management and adversely affects the capacity to take full control of the business activities in accordance with the criteria set out

2.2 Mining technology

Mining technology is important in the sustainable development of the stone mining industry Therefore, it is necessary to conduct research and classify mines by terrain conditions and sizes; classify the ES and its applying conditions; add and define the parameters needed in the design and production process; apply the technology that is flexible to work in complex terrain conditions, taking into account the investment capacity of businesses

CONCLUSION OF CHAPTER

Management and mining technology are two important factors that influence the sustainable development of the stone mining for construction in Vietnam The content of the thesis research should be focused on these two tasks

CHAPTER 3 RESEARCH ON TECHNOLOGICAL SOLUTIONS TO ENSURE SUSTAINABLE DEVELOPMENT OF BUILDING STONE MINING IN

VIETNAM 3.1 Classification of stone mines used for construction materials according

to terrain conditions and the size of the mine

According to topographic conditions, open pit mines can be divided into following categories:

Mines are located above the level of gravity drainage,

Mines are located below the level of gravity drainage,

Mines are located above and below the level of gravity drainage

To make it easy for the classification and selection of mining technology, mines located higher than the level of gravity drainage can be divided into groups:

a Single rocky mountain with foothills having circular circumference on the scheme or having the same dimensions; plain surrounding terrain; relatively small foothills’ perimeters

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b Rocky mountain composed of a cluster of many different ridges of different elevations; foothill clusters having circular circumference on the scheme or having the same dimensions; plain surrounding terrain; relatively large foothills’ perimeters

c Rocky mountain in form of long range; foothill’s length several times

as long as the width; many different ridges with different elevations; plain surrounding terrain

d Rocky mountain in form of long range leaning against another rocky mountains; only one exposed size, or two exposed sides with one surface being smaller

e Rocky mountain or peaks of 50-70m high; moderately steep slopes; 7m-thick soil cover

3-3.2 Research on classification of mining system for construction materials

in Vietnam and applying conditions

3.2.1 General overview of mining system and the classification of mining system

There are many different perspectives of SE classification, but all of them have the following common characteristics:

Based on the direction of movement and the growth of work route,

The main working object for classification is stripping stone,

SE is classified in general, irrespective of any specific mineral,

Terrain conditions are not taken into account

With respect to construction stone, a more appropriate ES needs to be studied

3.2.2 Classification of SE in stone mining for construction materials

3.2.2.1 Available classification

There are many researches, classifications of Vietnamese and foreign scientists such as Professor N.A.Maluseva, Dr Nguyen Thanh Tuan, Prof., Dr Tran Manh Xuan, and Ass Prof Dr Ho Si Giao, Ass Prof Dr Bui Xuan Nam

- The location of the mine compared to the level of gravity drainage;

- Cutting method on the horizontal surface;

- Conveyed method, shipping direction, the ability of combination transported by gravity and mechanism, working platform

- The selected mining ability;

- Waste dump location and drainage methods

3.2.3 Proposal of SE classification of building stone mine (table 3.3)

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3.3 Research and selection of suitable mining technology for building stone mines located above gravity drainage

3.3.1 Research and selection of opening up method

3.3.1.1 Access road for building stone mines in terrain group (a)

When mining in horizontal slicing of the building stone mines in terrain group (a), the spiral access road to transport is preferred The application of the spiral access road method depends on the height of rocky mountain, the foothills area Sd (m2), the first mining area St (m2), the overall mountain slope angle γ (degrees)

Hx = - S , m

S Ctg

sin sin b

3.3.1.2 Access road for building stone mines in terrain group (b)

When mining in horizontal slicing of the building stone mines in terrain group (b), the mixed access road to transport is usually applied, including general trench, which could be simple common trench in the quarry combined with part-cut subgrade and part-fill subgrade outside the mine From the end of the simple common trench or on favorable sites, the branched trenches circling through mountain’s waist to reach the mountain apron, eventually spiral access road for each mountain are dogged (Figure 3.3)

Figure 3.2 Dependence of trench height on road

bed width and overall mountain slope angle