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 IN VIETNAM Specialized: Mining Code: 62.52.06.03 SUMMARY OF ENGINEERING DOCTORAL THESIS HANOI - 2016 The thesis is completed at: Department of open pit mining, Faculty of mine, University of Mining and Geology Scientific supervisors: Prof Dr Tran Manh Xuan Vietnam Mining Science and Technology Association 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 PREAMBLE Rationale Vietnam possesses abundant mineral resources across the country for construction materials As such, the industry of mineral exploitation for construction materials is strongly developed to meet the needs of industrialization and modernization of the country 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associating with security, rational use of resources and environmental protection Reasons for these drawbacks include outdated mining techniques, especially in quarrying and insufficient licensing in some localities Therefore, the research is necessary and can contribute to the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 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 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 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 - 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 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 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 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 selfgovernance regulations based on the "Self-test" sheet 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 Overview of mining technology and the management of building stone mines in Vietnam and experience of stone mining in the world Chapter Analysis of the factors affecting the sustainable development of building stone mining in Vietnam Chapter Research on the technological solutions to ensure the sustainable development of building stone mining in Vietnam Chapter Research on management solutions to ensure the sustainable development of building stone mining in Vietnam Publications According to the research direction, 14 papers and/or abstracts have been published in magazines of mining, domestic and foreign conferences CHAPTER 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 T T Region / Type of Mineral Cement limestone Number of mines Million tons Paving stone Number of mines Million m3 Building Stone Number of mines Million m3 Northern highland Red river delta North Central Coast, Central Coast Central Highlands South East Mekong Delta Total 157 83 82 22 351 21,869.800 9,681.210 12,018.352 23,468 569,884 575,770 44,738.484 90 12 205 55 40 410 5,188.860 59.330 25,213.393 580.680 1,319.976 5,228.000 37,590.239 98 66 167 84 129 20 564 2,947.260 2,673.760 42,595.890 1,699.150 3,284.590 408.260 53,608.910 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 Category Unit Building million m3 stone Cement Million tons stone Paving Million m2 stone 2010 2015 2020 Demand Output Demand Output Demand Output 115 104 164 148 226 204 65.59 59.02 99.5 88.5 > 112 112 11.5 16.3 14 25 20 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 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 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 1015 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 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 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 - 20m3, excavator with bucket capacity of - 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 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 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 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 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 d - St  Ctg (3.1) ,m The parameters of the access road affects to the volume of road as: road bed width (m), trench height hh (m) and slope angle of the trench banks  (degrees): hh = b sin  sin  ,m sin(  -  ) (3.7) The correlation between trench height and road bed width, overall mountain slope angle is shown in figure 3.2 From figure 3.2, it can be seen that when the overall mountain slope angle less than 400, height of trench increases gradually, while overall mountain slope angle more than 40 0, the trench height increases rapidly, which indicates the ability of making the spiral access road on steep slopes is restricted  28,6 Figure 3.2 Dependence of trench height on road bed width and overall mountain slope angle ChiỊu cao cđa hµo (m) ³²  ³² 20 ³² b = 7,5m 16,4  ³²  ³² b = 5m  ³²  ³²      ³² ³²b×nh ³² Gãc trung cđa s-ên³² nói (®é)³² 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 partcut 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) 11 00 10 20 30 Figure 3.3 Chart showing access road can be applied 40 50 60 70 10 D 100 90 when exploiting the mountain peaks B, A, C, D and E B 40 70 60 50 30 20 10 00 E A 50 40 30 3.3.1.3 Access road for building stone mines in terrain group (c) When applying SE in horizontal slicing and transporting by truck, two approaches are applied: simple access road along one side of the mountain side, or spiral access road at two mountain ends When applying SE in vertical slicing and transporting by bucket excavator or bulldozer, the access road is built primarily for excavator, bulldozer or truck; the access road is designed on one mountain side, while other side is designed for stone transportation The lower slope mountainside is for access road, while the steeper slope mountainside is used for transport stone from the top 3.3.1.4 Access road for building stone mines in terrain group (d) If the length of mountainside is long enough and slope angles are not great, the simply access road or spiral access road are allowed, then the SE in horizontal slicing and transporting by truck can be applied If this SE method is not applicable, then the SE in vertical slicing, shoveling and transporting by bucket excavator, using bulldozer for vertical slices; or mining in horizontal slicing for the upper and mining in vertical slicing for the lower are applied 3.3.2 Determine the area of initial cut plan (leveling plan) The area of initial cut plan must meet the following conditions: - Ensure the normal operation for loading, transport equipments while clearing stones in the top leveling process - Ensure the access road can reach to the altitude of the open up location 3.3.2.1 Determine the area of initial cut plan when opening up by spiral access road and transporting by truck (mine in terrain group a) Considering the most difficult case that the access road is dug from this contour to next contour (with the height h), where the initial cut plan is located, must go through a spiral rt is notation of the converted radius of the area of initial cut plan: 12 00 40 30 20 50 80 70 C (1), (2), (3), (4) and (5) Section of first initial cut 60 80 for building stone mines in terrain group (b) rt = h Kd (  ctg )m  i (3.10) Subsequently, the area of initial cut plan is calculated according to condition of opening up and transporting by truck: St = rt2 , m2 (3.11) When using bucket excavator for clearing rock and leveling tops on the initial cut plan, the minimum area is (calculated via converted radius rt ') r 't  3R q 2mo  0,5bo  Lo ,m (3.12) Surface area calculated by rt’ is: St’ = r’t2, m2 (3.14) Where: Kd – access road stretching coefficient; - The overall mountainside slope, degree; i - slope of access road, degree; Rq - The minimum radius of curves in haul road, m; mo- safe distance from the edge of mountainside to the trail of vehicle, m; bo – Width of truck, m; Lo – Length of truck, m The selection of the initial cut plan using converted radius rt and rt ', the greater value will be selected 3.3.2.2 Determine the area of initial cut plan when opening up by spiral access road at two mine ends or simple access road for mining in terrain group (c) * Mining in horizontal slicing and transporting by truck In normal conditions, the length of initial cut plan can be approximated by equation 3.15: Lt = h  Rq , m i (3.15) Where: h – height of working bench, m; Width of the initial cut plan Bt = k (Rq + mo), m (3.16) Where: k - Additional coefficient * Mining in vertical slicing and transporting by excavator The minimum width of the initial cut plan must be equal to the width of mining strip, and the length is equal to minimum length of the shoveling stream 13 * Mining in vertical slicing and transporting by bulldozers Minimum length of the first initial cut plan can be identified by equation 3.15, and the width is equal to the width of normal mining strip 3.3.3 Research on applicable SEs 3.3.3.1 Research on applicable SEs for mines in terrain group (a) Applying SE in horizontal slicing and transporting by truck The spiral access road is the most favorable After completing the pike leveling and creating the initial cut plan, the first working bench can be started The most convenient position for first slice is at intersection between access road and initial cut plan (Figure 3.7) 20 mining 10 Figure 3.7 Diagram showing the initial cut plan in slice 1 Contour line 40 Axis of spiral access road Mặt bạt +50 m Initial cut plan Excavator Truck 10 20 Applying SE in horizontal slicing, shoveling by loading machine, then transporting along access road to truck at mountain apron When there is only one loading machine on mine, the mine’s yield will be equal to productivity of loading machines, determined by the equation: Qđ  60 EK x K ot H K 60 t xđ  2(rct  ct d ) i 1000 vtbc , m3/h 3.21) Truck load q0 also be calculated according to the equation: q0  120 L  Td  Tm vtbo  H K  Kq 0,12 ( N  1) t xd  (rct  ct d )  vtbc i   Ek x d , ton (3.28) Where: E – bucket capacity of loading machine, m3; Hct - mountain height calculated at the time of exploitation, m; rct - converted radius of corresponding 14 mining area Hct; Kd – access road stretching coefficient; vtbc - average speed of loading machine, km/h; Kot - operational efficiency coefficient; Kx – shoveling coefficient The loading machine’s productivity depends on the height of the mining location and the change is illustrated in Figure 3.9  ³²  Figure 3.9 The change of the loading machine’s ³²  productivity (WA 600-3, E = 6,1m3) depends on the height shoveling - transporting - unloading Slope of access road i = 12% Slope of access road i = 15% Slope of access road i = 18% Năng suất máy chất t¶i (m 3/h) of mining location when loading machine worked as ³²  ³²  ³² ³²  ³²  ³²  ³²  ³²  ³²  ³²    ³²cao khai ³² th¸c³² ChiỊu (m)  ³² Applying SE in horizontal slicing and transporting by loading machine or bulldozers through the trough When using this SE, the exploitation height can be upgraded, the volume of pike leveling and access road can be decreased; this method is applied for rocky mountain with restricted area of mountain apron The downside is that only one trough can be installed so that its yield is limited If considering the working time of loading machine, who loads stone into trough and time of bucket excavator, who clears the stone pile at the foot of trough are the same and equal to t, the productivity and capacity of loading machine and bucket excavator can be calculated by using the equation bellow: Qct = Vd 60.Ec K x kot  t Tck , m3/h Where: Ec = Vd Tck 60t.K x kot m3 (3.41) And: 15 Qg = Vd 60.Eg K x Kot  t Tcg , m3/h Where: Eg = Vd Tcg 60t.K x kot , m3 (3.42) Where: Kx – Shoveling coefficient; Kot - operational efficiency coefficient; Tck – Working cycle time of the loading machine, minutes; Tcg - Working cycle time of the cable bucket excavator, minutes 3.3.3.2 Research on applicable SEs for mines in terrain group (b) The SEs can be applied: When the mountain peaks are separated by a relatively large distance, and the spiral access road can reach to the initial cut plan at the height of pike leveling, the SE in horizontal slicing and transporting by truck can be applied In case truck cannot travel to the initial cut plan at the height of pike leveling, the SE in horizontal slicing, shoveling and shipping directly by loading machine, then unloading into truck at the mountain apron will be applied Applying SE in horizontal slicing and transporting soil and stone by trough by loading machine In terms of steep slopes at the lower mountain part which is not suitable for access road, then the conveyer trough to pour stone top down will be applied 3.3.3.3 Research on applicable SEs of mechanized mining for mines in terrain group (c) and (d) When the slope of the mountainside is unsuitable for access road, the SE in horizontal slicing and transporting by shoveling and bulldozer the stone over pit slope to mountainside Practically, the mixed SEs is applied Mining rock volumes in block for meter length along the mountainside with the mining strip width A (m) and bank height h (m) calculated by equation bellow: V1 = A.h , m3 (3.58) The volume of stone in solid mass falling and cumulating at mountain apron with the suitable rock pile height HCP (m) for shoveling is calculated for meter length by the equation bellow: 16 V2 = b H cp 2Kr = H cp2 (ctg - ctg ) It is well known that: Ah = 0,5 H cp2 2K = H cp2 sin( -  ) , K r sin sin m3 (3.59) V1 = V2, hence: sin( -  ) sin sin K r = 0,5 H cp2  Kr Rock pile height HCP (m) at mountain apron should be Hcp = 1,2 Hxmax (Hxmax - the maximum working height of excavators) and  = sin(  -  0) sin .sin  , we have: 0,72..H 2x max Ah = , m2 Kr (3.61) 0,72..H 2x max A= ,m K r h The increase in Ah has important meaning as it increases the bank height as well as promoting the working parameters of excavator; thereby mining efficiency is increased in general The mining strip width A = Amin to ensure the movement of excavator for starting the new mining strip (A  Amin), for the maximum bank height is suggested; then the bank height will be calculated by equation bellow: 0,72..H 2x max hmax = ,m A K r (3.65) Time of moving of the excavator to fully exploit the rocky mountain: Tdk = Ltbn H tb B tb 1000 v h A ,hour Where: Btb - The average width of the rocky mountain, m Ltbn - The average length of rocky mountain, (m) Htb - The average height of the rocky mountain, m For a particular mine, Ltbn, Htb, Btb are determined, the velocity v depends on the type of excavator is known, therefore moving time of no load excavator is inversely proportional to Ah Ah increase will reduce T dk Table 3.8 shows bank height and width of mining strip that might be applied for for some type of excavators 17 Table 3.8 Suggestion for selection of bank height h and width of mining strip A for different excavators Types of excavator working at foot of Seq the line and on the bench Front shovel CAT5680 (made in America) Front shovel ЭҐ-6 (Made in Russia) Bucket excavator – construction type Э2505-XD-2 (Made in Russia) Capacity Shoveling Bank of bucket height height m3 Hxmax, m h, m Width of mining strip A, m Applied borehole diameter, mm 5,2 11,12 10,0 6,88 105 6,0 13,0 12,0 7,8 127 2,5-3,2 10,0 8,0 7,0 105 3.3.4 Study on application of selection criteria for appropriate mining technology In the case of options for comparison are relatively simple and short time mining, the following criteria are applied Ci = Cki + Ed.Ki, đ/m3 (3.71) Where: Ci – Costs calculated for exploiting1m3 monolithic rocks under option no i, đ/m3; Cki - Costs for exploiting1m3 monolithic rocks under option no i, đ/m3; Ed - The coefficient of efficiency norms for investment; Ki - Basic investment rate, đ/m3 In the case of options for comparison are relatively complex and long time mining, the Net Present Value (NPV) criteria will be applied: n NPV =  (G t - C t )a t  max NPV  (3.72) t 0 Where: at - Discount factor in year t, Gt - Cash flow received in year t, Ct Cash flow spent in year t CONSLUSION OF CHAPTER The mine classification according to type of terrain conditions and mine’s size is studied and determined in order to set up the basis for the selection of SE and mining equipment synchronization The theoretical and practical issues on design and specific calculation methods for parameters of open up, parameters of SE, order of bench preparation for group mines in mountain area are completed and upgraded 18 CHAPTER STUDY ON MANAGEMENT SOLUTIONS TO ENSURE SUSTAINABLE DEVELOPMENT OF BUILDING STONE MINING SECTOR IN VIETNAM 4.1 The specific recommendations of modalities for mining licensing Scale of reserves for auctioned mining rights cannot take arbitrary but must be within a certain limit to ensure business profits; especially for mines located below the gravity drainage Vxdh (G - C) = max Vxdh (G - C) > (4.1) Where: Vxdh - Reasonable scale of stone reserves that business must pay for mining rights; G - The value of a unit of building stone is mined (monolithic), đ/m3; C - Total costs for the exploitation and processing of 1m3 building stone, đ/m3 Value of Vxdh is determined from volume of certain building stone Vxd located inside the outskirt of mine Value Vxd is calculated by using preselected size of pit floor; ensure mine and transport equipments to operate normally at a minimum level; depends largely on mining depth (Figure 4.1) 4.1.1 Determination of the volume of building stone Vxd Bm ß ß Bt ho Ho   Bd Lm A ß ß Lt ho Ho d d A Ld Figure 4.1 Chart of determining the volume of building stone Vxd 19 Final equation for determining the volume of building stone Vxd:  2S  H ( B  '  L  )   'H  d d d Vxd=  Sd2  (Bd '  L d ) H Sd   ' Sd H 02  H  (4.9) Where: Bd – width of pit floor, m; Ld length of pit floor, m; Sd - area of pit floor, m2; H0 - the mining depth of the mine, m; 1 – pit slope towards the bank, degrees; 2 – pit slope towards the pillar, degrees; d – pit slope of two mine end banks, degrees;  = ctg1 + ctg2; ' = 2ctgd 4.1.2 Determining the volume of cover on building stone The equation for calculating volume of cover on building stone is: Vp =  St  h 0ctg  ( Lt  Bt )  2h 02ctg   h0, m3 (4.15) Where: Bt –upper width of mine is calculated for building stone, m; L t upper length of mine is calculated for building stone, m; St –upper surface area of mine, m2;  - Stable angle of the cover, degrees; h0 - thickness of cover, m 4.1.3 Determining the cost of mining and processing of building stone General equation: Cxd = Ckn+Cxb+Cvt+Cns+Ctn+Cd+Cmt+Cg+Ctp+Cq+Ck, đ/m3 (4.16) Where: Costs for exploitation and processing of 1m3 building stone (Cxd) including: cost of drilling and blasting (Ckn), shoveling and loading (Cxb), transporting (Cvt), crushing and screening (Cns), cost of surface and groundwater drainage (Ctn), compensation or leasing land for mining (Cd), environmental protection fee (Cmt), fee for granting mining rights (Cg), royalty and other fees (Ctp), management costs (Cq) and other expenses (Ck): On the other hand, this cost is also determined by the equation: Cxd = A + B Dong/m3 (4.30) Where: A - Part of the cost does not depend on the depth of exploitation, đ/m3; B - Part of the cost depends on the depth of exploitation, đ/m3; B = 0,5[Bd + Ld + 2hoctg + h0 Kd K Sc  ] + 0,5[ d + 0,5 (ctg1 + ctg2 + ctgd] + L 1000 i i ( H o  ho ) SmF  36590 S m  0,35 Pm ( H o h o )  0,5( H o h o ) ].S dm đ/m3 ( )C bn  [ Ad V xd Where: Sm – mine’s surface area, m2; i - slope of access road, đv 20 (4.29) 4.1.4 The determination order of the reasonable scale of building stone reserves The method of valuation of Vxdh is as same as determination of the reasonable depth of the mine exploitation when size of pit floor is known When the appropriate depth is determined, the volume of building stones in that depth range will be determined Profits earned from the quarrying include two parts: The part of building stone mining L1 and part of exploitation and use of cover layer L2 Total profit: L = L1 + L2> and Where: L1 = Vxd(G - C) L2 = Vp(Gp - Cp) Where Gp and Cp - the entire value and cost of removing 1m3 cover layer When using informatics to solve the problem, the block diagram is as following (Figure 4.2) Figure 4.2 Block diagram defining reasonable scale of building stone reserves for auction of mining rights 21 Based on above outlined block diagram, software for reasonable calculation of stone reserves for auction of mining right is written The software is written in C# language in the most minimalist form After the input parameters are entered, the software will calculate and the output table (4.1), (4.2) and (4.3) will be given, which can be managed, stored, meeting the requirements for easiest reference INTRODUCTION OF SOFTWARE FOR REASONABLE DETERMINATION OF MINING RESERVE Running the program  Select "Calculate" on Menu bar  Enter data into the program  Select the output as individual table of results In this process, the destination folder to save the results should be chosen 22 4.2 The specific recommendations on state management 4.2.1 Management on planning Management of mining activities based on approved plan Compiling the adjacent separated small mines into a large mine 4.2.2 Comprehensive inspection based on "Self-test sheet" The first stage: From the time of granting mining license to the time that project finish development opening and the mine into operation The second stage: Normal production phase of the mine The third stage: The mine closing Comprehensive inspection based on "self-test sheet" 4.2.3 Research formulating mechanisms to coordinate inspection building stone quarrying operations across sectors and between the central and localities Promulgate regulations on coordination, exchange of information and periodic reports; Strengthen the organization of state management agencies on minerals CONCLUSION OF CHAPTER The licensing should be considered to ensure the normal operation of the mine Incentive policies should be made to cooperate for exploitation on a large area, facilitate the application of advanced mining techniques Continue to nurture, capacity building and enhancement for staff who work in the field of state management on minerals There should be consistency between the central agencies and between the central and local authorities in the inspection, testing on the basis of the content of "Self-test sheet" Use the reserve calculation software to determine the scale of mines CONCLUSION In this thesis, mining technology for building stone in the different conditions in Vietnam and other countries has been reviewed and assessed, and based on that, technology solutions suitable for the specific conditions in Vietnam have been discussed, completed and selected Mine types have been classified according to terrain conditions and sizes for the selection of mining technology and device synchronization Exploitation 23 system of building stone mines has been classified according to distinctive characteristics that thoroughly express the surveying elements Moreover, some theoretical and practical issues of design were improved in the field of opening up, initial cut plan identification for mining, and method for creating original mining strip when moving to new mining layer, selection of SE parameters such as bench elevation, mining strip width when mining in vertical slicing and transporting by truck is applied Solutions for mining licensing were addressed with specific criteria in order to facilitate mining enterprises to apply technological advances in mining More efficient licensing also helps ensure safety and maximum resource recovery, environmental protection and makes mining associate with the socio-economic planning as well as mineral planning In order to address the issue of mine fragmentation, overlapping exploitation, concrete policy should be in place, and small enterprises should be encourage to cooperate to form a larger mining company so that more advanced technology will be applied to ensure efficiency, security and environmental protection Specialized staff should be equipped with knowledge of mining technology The inspection should be conducted in 03 stages as proposed by the thesis, with each stage having a specific content to ensure normal operation and effectiveness of mining businesses It is recommended to apply forms of checking under "Self-test sheet" RECOMMENDATIONS It is recommended that Ministry of Natural Resources and Environment propose the Government new mining licensing policy The improvement should be focused on mine’s sufficient space for normal operation and sufficient time for effective operation Reorganize, compiling the adjacent small separated mines into larger mines so that enterprises have more financial capacity to apply advanced mining techniques for greater efficiency and better environmental protection With regards to mines planned for new investments or full mechanization, it is recommended to apply mining and transportation equipment with high mobility to operate well in complex terrain conditions when combining them in the different technology diagram 24 PUBLICATIONS Hoang Cao Phuong, Nguyen Xuan Quang (2011), “Present status of white silica sand mining in Quang Nam – Thua Thien Hue area and sustainable development orientation”, p.36-38, Journal of Mining Industry No.3-2011; Hoang Van Khoa, Hoang Cao Phuong, Nguyen Xuan Quang (2011), “Overview on minerals resources of Vietnam”, p.39-42, Journal of Mining Industry No - 2011 Hoang Cao Phuong, Nguyen Xuan Quang (2011), “Some contents of Mineral Law 2010”, p.50-52, Journal of Mining Industry No 4-2011; Hoang C Phuong, Nguyen X Quang, Bui X Nam (2010), “Current situation of white sand mining in Quang Nam and Thua Thien Hue provinces and orientations for sustainable development”, Water Resource Protection and Management, GAG Group Workshop, pp.16 - 22 Hoang Cao Phuong et al (2012), “Some management solutions on mining activities in Thai Binh river and Kinh Thay river in Hai Duong province”, p.53-54 and 57, Journal of Mining Industry No 2-2012; Hoang Cao Phuong, (2013), “Present status of minerals activities licensing for the first six month 2013 of the Ministry of Natural Resources and Environment ”, p.18-21, Minerals Specialties No 2-2013 Hoang Cao Phuong, (2013), “The minerals activities licensing in 2013 and some directions for 2014”, p.22-26, Minerals Specialties No.3-2013; Hoang Cao Phuong, (2014), “Improving the quality of the work on receiving and appraising the dossiers for minerals activities licensing”, p.10-12, Minerals Specialties No.1-2014; Tran Manh Xuan, Hoang Cao Phuong, (2014), “Management, mining and efficiency of building stone open pit mines toward the sustainable development”, p.69-73, Journal of Mining Industry No.5 - 2014 10 Hoang Cao Phuong, (2014), “Some issues on classification of exploitation system for building stone mines”, p.42-45, Journal of Mining Industry No - 2014 11 Hoang Van Khoa, Hoang Cao Phuong, (2015), “Management, mine licensing for cement limestone and industry limestone in Vietnam, p.89-91, Journal of Mining Industry No - 2015 12 Hoang Cao Phuong, Luong Van Hung, (2015), “Status and direction of mining technology for cement limestone in Vietnam”, p.85-88, Journal of Mining Industry No 3-2015 13 Tran Manh Xuan, Hoang Cao Phuong, (2015), “Mechanized and use of flexible technology for building stone mines in complex terrain and size limited”, p.1-3 and 22, Journal of Mining Industry No.3 - 2015 14 Tran Manh Xuan, Hoang Cao Phuong, (2015), “Status of mine licensing after enforcement of Mineral Law 2010 –Situation and solutions”, p.115-118, Journal of Mining Industry No - 2015