tóm tắt luận án tiến sĩ tiếng anh nghiên cứu xác định chỉ tiêu thuốc nổ nhằm đảm bảo mức độ đập vỡ đất đá hợp lý cho một số mỏ khai thác vật liệu xây dựng của việt nam

MINISTRY OF EDUCATION AND TRAINING UNIVERSiTY OF MINING AND GEOLOGY The dissertation was completed at: Surface Mining Department, Mining Faculty, University of Mining and Geology Science Instructor: GS.TS Nhu Van Bach, University of Mining and Geology nguyen dinh AN TS Nguyen Dang Te, VINACONEX Reviewer 1: TSKH Nguyen Thanh Tuan - Vietnam mining science and technology association RESEARCH ON DETERMINING POWDER FACTOR TO ENSURE A PROPER FRAGMENT SIZE FOR LIMESTONE QUARRIES IN VIETNAM Reviewer 2: TS Nguyen Phu Vu - Vietnam mining science and technology association Reviewer 3: TS Nguyen Sy Hoi - Vietnam mining science and technology association Branch: Code: Mining Engineering 62520603 The dissertation will be defended before the Council of Doctoral dissertation assessment help at Hanoi University of Mining and Geology at …………… on………………2014 SUMMARY OF DOCTORAL DISSERTATION The dissertation can be found at the National Library in Hanoi or noi - 2014 Library University of Mining and Geology INTRODUCTION Urgency of subject In mining industry in general and open pit mining in particular, blasting is an important which influences directly loading, haulage and milling phase Nowadays, there are many achievements in research of blasting theory and blasting material in mining industry, especially of blasting parameters for improving rock fragmentation efficiency Powder factor is very important in blasting Explosive cost used to break a volume unit of rock according to requirement and blasting mission is called as powder factor Powder factor is a blasting parameter which depends on physical and mechanical characteristic of blasting, size requirement of rock fragmentation, explosive type, blasting technology, other blasting parameters and so on Some equations of powder factor have been applied in Vietnam However, they are not close to practice in mines due to factors influencing powder factor are determined not accurately According to mining experiences from overseas and disadvantages of blasting in open pit mines, especially in quarries in Vietnam, research on determining powder factor to ensure a proper degree of rock fragmentation for some quarries in Vietnam is very urgent Annually, there are millions m3 of rock blasted and hence, if good calculation of powder factor can be done to decrease 1÷2%, the amount of explosive used will be reduced considerably Research results will assist mining companies being more active in blasting and improving their business and production which contributes to ensure investment efficiency for new technology and more safety for humans and surrounding environment Therefore, the PhD dissertation “Research on determining powder factor to ensure a proper fragmentation size for limestone quarries in Vietnam’’ is very urgent, satisfying practical demands in mining industry in Vietnam 2 Research purposes of dissertation Based on explosives materials made in Vietnam and theory, research works in domestic and from overseas as well as experimental results of research on relations of factors affecting powder factor I propose a method to determination of reasonable powder factor to ensure a proper fragmentation size for limestone quarries in Vietnam, which used for some limestone quarries in Vietnam to improve economic and technical standards of blasting Object and research scope - Research object is determining powder factor to ensure a proper degree of rock fragmentation for quarries, mainly in Vietnam - Research scope is blasting practice in quarries in Vietnam Research content - Research on blasting technology in mining, powder factor and other blasting parameters - Research on factors affecting powder factor - Research on relation between powder factor and explosive degree and degree of rock fragmentation - Research on determining powder factor to ensure a proper degree of rock fragmentation for quarries in Vietnam Research methods - General method, analytical and comparative method, inheritance method, statistical and graphic method - Theoretical and experimental method Scientific and real significance Powder factor is an important blasting parameter affecting and relating closely to other blasting parameters Accurate determination of blasting parameters plays the decisive role in quality and efficiency of blasting in mines Research result is creating a method to determine powder factor based on a scientific foundation and a relation between powder factor and impact coefficients, ensuring it is employed favorably in quarry mining 3 Research result can be applied in quarries in Vietnam and guarantee efficiency and reduction of impacts on environment Theoretical points to defend Powder factor is a basic one which plays an important role in blasting in quarries Impact coefficients of powder factor are divided into two groups: group of variables and group of coefficients Technical powder factor (qcn) determined according to required degree of rock fragmentation (dtb) and degree of crack (dmax) is a foundation to determine powder factor for any blasting conditions Relation between qcn dtb is linear Reasonable powder factor in quarry mining is determined by technical powder factor (qcn) combining theory with experiment based on qualitative relation between powder factor and two impact groups New points of dissertation Determining powder factor for quarries using explosive made in Vietnam, millisecond delay non-electric blasting technique and based on required degree of rock fragmentation in quarry mining Based on relation between powder factor and impact coefficients, classification of the impact coefficients is made by dividing them into two groups which are better in determining an optimal powder factor Function of powder factor is made according to classification of groups of impact coefficients The software for designing blasting report is build from a proper powder factor Composition of the dissertation The dissertation includes more than 145 pages and lots of tables, graphs, figures and references in domestic and from overseas Generally, except introduction and conclusion part, the dissertation composites the following chapters: Chapter - Overview of researches of powder factor and other blasting parameters Chapter - Research on impact factors of powder factor Chapter - Relation between powder factor and explosive degree and degree of rock fragmentation Chapter - Research on determining powder factor to ensure a proper degree of rock fragmentation in some quarries in Vietnam Publications Based on research trend shown in the dissertation, I have 15 research works which are published in journal of mining industry and domestic and international conferences CHAPTER 1: OVERVIEW OF RESEARCHES OF POWDER FACTOR AND OTHER BLASTING PARAMETERS 1.1 OVERVIEW OF BLASTING TECHNOLOGY IN MINING Valuable deposits are often extracted by open pit or underground method in which mostly rock with hardness degree of f = 6÷14 and 70% of valuable materials are necessary to break into desired size Currently, rock fragmentation methods are done mainly by blasting using boreholes and small holes 1.2 ROLES OF POWDER FACTOR IN MINING One of the most fundamental standards used in evaluating efficiency of rock fragmentation is size of blasted rock or degree of rock fragmentation This degree depends on mining equipment dimension (bucket capacity, haulage method, and milling) Whereas, powder factor is a key parameter to determine the degree of rock fragment 1.3 SOME DIFINITIONS OF POWDER FACTORS 1.3.1 Calculated powder factor, q This powder factor is used to calculate and for initial design or carrying out initial blasting in specific conditions according to requirements of blasting Some other authors treat it like powder factor 1.3.2 Practical powder factor, qth This term helps companies improve their management as well as it is a real value which is used in blasting under the same condition The reason is that practical powder factor only is calculated after finishing blasting and loading works 5 1.3.3 Powder factor for creating standard explosion crater, qc Powder factor for creating standard explosion crater is the costs pending in breaking a bank volume unit of rock to create a standard explosion crater 1.3.4 Standard powder factor, q0 The quality of blasting is evaluated by the size of rock fragmentation Hence, standard powder factor is the adequate cost spending in breaking a bank volume unit of rock to get required size of rock fragmentation (in standard explosion condition) 1.3.5 Reasonable powder factor, qhl Reasonable powder factor is the adequate cost spending in a volume unit of rock so that the total cost of all technological phases is minimized factor Impact coefficients can be divided into some groups as followings: Group 1: Factors characterize environment of blasting such as physical and mechanical properties of rock, degree of hardness, degree of crack, rock density, Group 2: Factors of explosive are used as a standard Researches can be choosing Ammonite No6 or ANFO to be a standard explosive depending on explosive production industry, blasting condition and rock properties in each country Group 3: Researches also are interested in parameters of blasting pattern, especially in diameter of charge, d Other parameters are admitted only in qualitative aspect and only mollifying with a rational factor in quantitative aspect depending on specific blasting conditions or just according to experimental values Group 4: In case of control blasting methods such as millisecond delay blasting, decked charge blasting, high bench blasting and blasting in high pressure, researches often choose an experimental factor to evaluate Research method and equation foundation go through three steps as followings: Step 1: Doing a research on the theory of relation between powder factor and its impact coefficients Step 2: Carrying out experiments in lab or industrial experiments to determine some quantitative values Step 3: Establishing a specific relation between powder factor and relevant coefficients Besides, factors having a little or no impact will be are experimental values 1.6.2 Problems existing in researches on powder factor a Researches not concern fully features of power properties of explosive in selecting explosives which are used as a standard in calculating b The introduction of millisecond delay blasting method (1934 ÷ 1935) and non - electric facility (1970 ÷ 1973) has been brought a big efficiency in open pit mining Millisecond delay non-electric blasting 1.4 OVERVIEW OF BLASTING PARAMETERS IN SURFACE MINING There are two types of blasting parameters in open pit mining including: parameters of drilling pattern and parameters of explosive charge 1.5 OVERVIEW OF RESEARCHES ON POWDER FACTOR Relevant researches on powder factor includes as followings: - Method of determining powder factor according to required size of rock fragmentation (Kuznetsov, B.N Kutuzov) - Method of determining powder factor according to power of explosive (I.P.Oxanhit and P.X Mirônov) - Method of determining powder factor according to standard powder factor (V.V Rjevxki) - Method of determining powder factor according to the rule of size distribution within blasted rock heap 1.6 EVALUATION OF RESEARCHES ON POWDER FACTOR 1.6.1 Comments about researches published on powder factor All researches admit that powder factor is a fundamental parameter which affects directly the quality of rock fragmentation and cost of mining product Almost researches evaluate accurately about factors in qualitative aspect which affects the determination of value of powder using modern firing facilities is better than others because of some advantages as followings : - Being able to control the degree of rock fragmentation due to increase impact time of explosion and crushed control zone on rock - Being able to widen drilling pattern (due to create a large free face) and simultaneously, ensure the quality of fragmentation Hence, it contributes to decrease drilling cost - Reducing power factor whereas improving quality of fragmentation - Being able to increase blasting scale and control ground vibration - Millisecond delay non-electric blasting improves quality of fragmentation and reduces harmful effects on environment (especially ground vibration) However, scientific foundation of efficiency of rock fragmentation of millisecond delay non-electric blasting is researched not comprehensively in Vietnam c Rock broken by blasting is a complex environment in which it is non-identical and isotropic Explosion process occurs very quickly so that determining stress state of each point is very difficult Using equivalent materials to model explosion samples and experimental factors to converse it into practical environment in blasting are often make a large error d Equations established are often complicated or contain lots of experimental factors which reduce ability to apply in practice e In general, all researches in domestic and from overseas affirm that the degree of rock fragmentation (shown in diameter of grain size) influences considerably power factor At the moment, there is no research which solves deeply and completely this problem and fixes with practical situation in quarries in Vietnam Hence, it is able to propose some problems to research next as followings: Establishing a method to determine a proper powder factor in quarries in Vietnam is based on: Using millisecond delay non-electric blasting method with explosive made in Vietnam (ANFO); required degree of rock fragmentation in quarries CHAPTER 2: RESEARCH ON FACTORS AFFECTING POWDER FACTOR 2.1 REQUIREMENTS OF BLASTING IN QUARRY - Grain size of rock fragmentation must be uniform and oversize rock must be very few - Dimension of blasted rock heap (height, width) must fix with loading and haulage equipments in order to ensure production and safety for them and being suitable with parameters of mining method - Bench floor must be smooth and limits postpulse and improves capacity factor of drillhole - Blasting activity must ensure strict safety for humans, houses and buildings under the effect of ground vibration, air blast and flying rock 2.2 FACTORS AFFECTING POWDER FACTOR - Factors are featured for environment which blast activity takes place - Economic and technical factors include blasting parameters, type of explosive being used, and firing method 2.3 COMMENTS AND EVALUATION OF RELATION BETWEEN POWDER FACTOR AND IMPACT COEFFICIENTS Coefficients affecting powder factor can be divided into two groups: Group of variables includes coefficients that affect directly and change powder factor continuously They are: + Chemical and physical properties of rock include hardness factor f and degree of crack + Required degree of rock fragment that is grain size of blasted heap rock and characterized by average size of rock Group of coefficients includes factors which influence powder factor in a certain level, depending on explosion condition, as followings: + Type of explosive + Method of firing control + Technology and technique of carrying out blasting 9 10 CHAPTER 3: RELATION BETWEEN POWDER FACTOR AND ROCK BLASTABILITY AND DEGREE OF ROCK FRAGMENTATION blasthole with diameter in 76÷105 mm, bench height in 7÷15m, bucket capacity in 2÷5 m3, millisecond delay non-electric blasting method (with non-electric facility), AD-1 explosive, ratio of oversize rock in heap less than 2÷3% According to experimental blasting and rock classification of M.M.Protođiaconov, rock classification table of Prof.Dr Nhu Van Bach & Dr Le Van Quyen et al, rock classification of blastability can be seen as follows: Table 3.1: Rock classification of blastability Easy Average q0 < 0,3 q0 = 0,31 ÷ 0,38 Very Difficult q0 = 0,39 ÷ 0.46 q0 = 0,47 ÷ 0,55: difficult q0> 0,56 Extreme difficult 3.2.3 Designing a software to rock classify of blastability 3.1 RELATION BETWEEN POWDER FACTOR AND DEGREE OF EXPLOSION Blasting considers rock as a main object to impact Degree of explosion characterizes how difficult to fire explosive are and is determined by powder factor under a standard condition The larger powder factor is, the higher degree of explosion is and vice versa 3.2 ROCK CLASSIFICATION IN MINING Classification of rock plays an important role in mining It is based on selection of drilling machine, method of firing, mining production norm and cost of blasting material 3.2.1 Foundation of rock classification Foundation of rock classification according to degree of explosion is powder factor qo Based on this factor, grain size of blasted rock heap distributes as a line on graph Method of determination of qo is as follows: experiment of blasting using two type of powder factor q1 and q2 is done two times for each type of rock and then determining property of grain size distribution with size x ≤ x0 ( P1 and P2) corresponding to two courses of blasting Finally, q0 is determined as followings: P1 P2 q0 = (q − q ) lg X L max q 1q lg , kg/m3 (3.1) Where: P1, P2 are percentages of grain size corresponding to x ≤ x0 in two courses of blasting q1 q2, respectively 3.2.2.2 Result of rock classification of blastability for some limestone quarries in Vietnam This method was applied for experiment in some limestone quarries such as Ninh Dan – Thanh Ba – Phu Tho limestone quarry (owned by Song Thao cement company), Van Xa – Thua Thien Hue limestone quarry (owned by LUKS Vietnam cement company), Thuong Tan IV – Binh Duong limeston quarry Quarries used Fig 3.1- Block diagram for determining standard powder factor Fig 3.2- Interface of software used to determine rock classification of blastability 3.3 RELATION BETWEEN POWDER FACTOR AND DEGREE OF ROCK FRAGMENTATION In order to evaluate efficiency of fragmentation, degree of lump (Dtb)is used In case of the same blasting condition, the larger powder factor is the smaller (Dtb)is Optimum requirement of grain size within blasted rock heap depends on mining equipment fleet (bucket capacity, method of haulage) 11 12 3.3.1 Proper degree of rock fragmentation 3.3.1.1 General definition of degree of rock fragmentation According to international researches, largest size of blasted rock is determined by loading equipment as follow: (3.2) D cp = (0,7 ÷ 0,8 ) E , m Where :Dcp–maximum size of blasted rock, m; E – bucket capacity, m3 Maximum size of blasted rock based on milling condition is determined as follow: Dcp = (0,7 ÷ 0,8)B, m (3.3) Where : B- minimum size of bin gate, m Degree of rock fragmentation is determined by diameter of grain size within blasted heap as follow: according to phases including: drilling; loading, hauling and milling, đ/m3; E – coefficient of investment efficiency 3.3.1.4 Proper degree of rock fragmentation for quarries In order to determine a proper degree of rock fragmentation according to technical conditions of quarries, it is possible to use some method as followings: - According to bucket capacity: D tb = ∑ γ iDi 100 (3.4) n i =1 n i + E ∑ K i → ; (3.5) i =1 Where: Ci – production unit of one m3 of rock according to phases including: primary blasting and drilling; loading, hauling and overisize rock breaking đ/m3; Ki– basic cost of one m3 of rock (3.6) Where: E – bucket capacity, m - Determining average size of blasted rock according to method of B.N Kutuzov D tb = Where: Di – average size of grain size of “i”; γ i - percentage of grain size of “i”, % 3.3.1.2 Determining degree of rock fragmentation Degree of rock fragmentation can be determined by methods as followings: - Determining average size of blasted rock Dtb by statistical power method - Determining average fragment size of blasted rock Dtb by semiexperimental method of V.M Kuzonhetxov - Determining average fragment size of blasted rock Dtb according to method of B.N Kutuzov - Determining average fragment size of blasted rock Dtb average method from evaluating size of blasted rock in practice 3.3.1.3 Evaluation of degree of rock fragmentation - Degree of rock fragmentation is reasonable if it ensures that total cost of a production unit in mining is minimum ∑C d tb = (0,15 ÷ 0,2)3 E D cp  Vqc   41 −  V  o   (3.7) Where : Vqc– percentage of size of blasted rock, %; Vo– percentage of natural cracking mass in bank being larger than required size of blasted rock According to statistical and analytical result of data from quarries in Vietnam, application of equation (3.7) is suitable to determine degree of rock fragmentation Here, required size of blasted rock Dcp is determined based on milling condition Maximum size of blasted rock depends on type and capacity of milling machine CHAPTER 4: DETERMINATION OF REASONABLE POWDER FACTOR FOR LIMESTONE QUARRIES IN VIETNAM 4.1 Research to the relationship between powder factor with element affect Determination of reasonable powder factor for limestone quaries in Vietnam to have research to relationship between powder factor with affecting element to blasting 4.1.1 Research to relationship between powder factor with explosives 13 For the selection explosives based on: - The first is characteristic of explosives - The second is the cost of explosives When determining powder factor by using other explosives, it is different from standard explosives must mention the conversion coefficient because the explosive energy is different 4.1.2 Research to relationship between powder factor with rock properties According to experimental and theory of blasting, the rock properties is the most important and directly affect to calculate powder factor 4.1.3 Research to relationship between powder factor with blasting parameters 4.1.3.1 Relationship between powder factor with charge diameter Definition of charge diameter that directly affect to Fragmentation size and cost of product However with the required of Fragmentation size should be increasing charge diameter because the large diameter overcome high bench and then extending drilling patterns, to reduce cost of drilling 4.1.3.2 Relationship between powder factor with hole spacing Through results research about the relationship level of powder factor with blasting parameters as charge diameter, bench high, hole spacing are little change, because there are depend on blasting requirements 4.1.4 Relationship between powder factor with blasting methods When calculating powder factor, blasting method is not the number variables of function powder factor, which is the only coefficient depends on blasting conditions 4.1.5 The relationship for the determination of Powder factor Fragmentation size This is important factor for determination of reasonable powder factor According to experimental and theory of blasting can confirm this relationship is linear function, it means: q = ϕ (dtb) = adtb + b (4.1) 14 4.1.6 The relationship for the determination of Powder factor - environment To protect the environment when blasting in limestone quarries as follows: - Using suitable types of explosives - Using suitable powder factor Fig 4.1- Powder factor depend on Fragmentation size - Using appropriate blasting parameters - Using reasonable blasting methods 4.2 DETERMINATION OF REASONABLE POWDER FACTOR FOR LIMESTONE QUARRIES IN VIETNAM 4.2.1 Analysis, assessment and classification of the elements affecting to powder factor Powder factor depends on rock properties, explosive types, blasting methods, blasting parameters, and required fragmentation The influence of each factor to powder factor is different, based on these properties it can be divided into two groups Group one: The factors directly influencing to reasonable powder factors: - Rock properties, (rock strength, rock fracture); - Required fragmentation, (average fragment size); These factors are variables Fig 2- Outline of illustrations of the function of reasonable function of powder factor and powder factors affecting factors x1, x2- The variables; k1, k2- the Group two: The factors affecting factors indirectly influencing to reasonable 15 powder factors, it means that the values of powder factor change in certain range The powder factor is a function Y, the affecting factors are variables x1, x2, May be function of powder factor such as: Y = f(x1, x2,….) (4.2) 4.2.2 Definition of optimum explosives Based on the requirements and characteristics of limestones quarries in Vietnam, using standard explosives are ANFO to calculation 4.2.3 Method of determination of powder factor for limestone quarries 16 Table 4.1: The results of determination fragment size Fig 4.3- interfaces software of Spit – Desktop - From the results of blasting test at limestones quarries, we builded the functional relationship between the average fragment size with powder factor is shown on fig 4.5, 4.6, 4.7 4.2.3.1 Powder factor depends on blasting requirements The research results indicated the distribution law of particle size and the function of powder factor with average fragment size is linear function: qcn = adtb + b (4.3) Where- qcn is technical powder factor, kg/m3; dtb is average fragment size, m; a, b is empirical coefficients, it found from empirical blasts For determination relationship between power factor Fragmentation size, author carry out blasting test at Ninh Dan limestone quarry, Thuong Tan limestone quarry, Yen Duyen limestone quarry as follows: - Rock hardness equal ÷ 12, degree of fracturing belong to level II III, IV; - After each blast carried out photographed and monitoring muck loading Used Autocad Spit – Desktop software for determination fragment size (Fig 4.3) The results of determination fragment size shown on table 4.1 and graph of fragment size distribution shown on fig 4.4 Fig 4.4- Graph of fragment size distribution Fig 4.5- Powder factor Fragmentation size relationship at Ninh Dan limestone quarry Fig 4.6- Powder factor Fragmentation size relationship at Thuong Tan IV limestone quarry Fig 4.7- Powder factor Fragmentation size relationship at Yen Dunyen limestone quarry 17 18 Base on results blasting test, if other affecting factor is not changing as rock hardness, type of explosives, fracturing, then only changing fragment size, to realize: - When dtb ≈ then qcn = qmax = b - When qcn = → = admax + b From data in table determine the relationship between quotient q1/qcn and rock hardness such as: q1/qcn = 0,635.f0,262 (4.7) Where q1/qcn is hardness coefficient This is coefficient k1 need to find The equation (4.6) becomes: → d max = − b a →a=− b d max Where: dmax – Diameter of medium fracture block in the rock mass Equation (4.2) then is becomes: q cn = − b (4.4) - According to the statistics from blasting at limestone quarries, maximum of powder factor (qmax) equal 0,8 kg/m3 Then qcn = qmax = 0,8kg/m3 → b = 0,8, The equation (4.3) becomes: d tb + ,8 d max (4.8) The powder factor can be determined by the following formula q1 = k1 × q cn = 0,635× f × q cn (4.9) 4.2.3.3 Powder factor depends on rock density d tb +b d max q cn = − ,8 k1 = 0,635× f (4.5) 4.2.3.2 Powder factor depends on rock hardness f The rock strength is estimated by hardness coefficient f, (M.M Protodiaconov's classification) When hardness coefficient increasing, Powder factor also increasing When mentioning the hardness coefficient, the formula of Powder factor is determined as follows: q1 = k1.qcn (4.6) According to the statistics, blasting test determination relationship between rock hardness power factor qcn and q1 shown on table 4.2 Table 4.2: Relationship between rock hardness power factor qcn and q1 Rock hardness (f) 10 11 12 Technical powder 0,25 0,28 0,32 0,35 0,40 0,45 0,48 factor qcn, (kg/m3) 0,30 0,35 0,39 0,46 0,53 0,58 Powder factor q1, 0,25 4 5 (kg/m3) 1,07 1,10 1,13 1,16 1,18 1,21 q1/qcn When mentioning the rock density, the powder factor can be determined by the following formula q2 = k2.q1 (4.10) For the limestons quarries in Vietnam, average rock density is 2,6 t/m3 According to the theory of blasting and blasting test coefficient k2 determined by the following formula: γ k2 = đ (4.11) ,6 Replace (4.10) in (4.9) and equation (4.9) then is becomes: γ q = đ × 0,635 × f × q cn (4.12) ,6 4.2.3.4 Powder factor depends on type of explosives When mentioning the type of explosives Using coefficient k3 is relative heat of explosives: k3 = Qtc/Q (4.13) Where: Q- heat of explosives using, Kcal/kg; Qtc- heat of standard explosives ANFO Powder factor can be determined by the following formula: γ (4.14) q = k × đ × 0,635 × f × q cn 2, 19 20 4.2.3.5 Powder factor depends on blasting method 4.2.3.6 Powder factor - blasting parameters and environment relationship VBA / Excel language help engineers easy to use for calculating blasting parameters, blast log quickly, exactly and reliably 4.3.1 Software structure Software including parts: - Part 1: General Information - Part 2: Determination of reasonable powder factor - Part 3: Determination of blasting parameters - Part 4: Drawing blasting patterns 4.3.2 Introduce some interfaces and results calculated by the software The relationship between powder factor - blasting parameter and environment is indirectly Method of determination of reasonable powder factor (qhl, kg/m3) does not take into account this relationship and also not shown in this formula From the results of the formulas (4.4 ÷ 4.14) to establish the final formula of determination of reasonable powder factor is becomes: Fig 4.9- General Information Today, the delay initiation method is used in all of the limestone quarries in Vietnam because of its many advantages The most common value of k4 when using delay initiation method will generally lie in the range of 0.85 to 0.95 Powder factor can be determined by the following formula: q3 = k4 × k3 × q hl = ,653 × f ( − ,8 γđ × , 635 × f × q cn ,6 (4.15) d tb γ + ,8 ) × đ × k × k , kg/m (4.16) d max ,6 The formula determination of reasonable powder factor shows full factors of influence on powder factor and meets the requirement and purposes of the blast as when changing fragment size, rock property, explosives type and condition of blasting for limestone quarries in Vietnam The results of calculations for a number of limestone mines are suitable with actual results The problems of this formula need to be more multiple blasting experimental to determine exactly influence coefficient 4.3 Build program calculates powder factor, blasting parameters and blasting patterns From the study, author have built the software calculates powder factor, blasting parameters and blasting patterns Programs written by Fig 4.10- Determination of reasonable powder factor Fig 4.8- Block Diagram of software Fig 4.11- Drawing blasting patterns 21 400 400 42 400 42 42 17 ÐKN 400 400 400 400 42 17 42 17 400 22 17 400 400 Fig- 4.12- Delay blasting patterns using non electric detonation Fig- 4.13- Delay blasting patterns using electric blasting cap Fig- 4.14 Interfaces of blast log GENERAL CONCLUSION Rock blasting is the first step in mining, especially in limestone quarries One of the most important blasting parameters needs caring is powder factor This parameter has considerable influence on other blasting parameters and the environmental impacts There are various natural and technological factors that influence on the powder factor Two groups classify the elements: fluctuation factors and constant factors In different condition, the powder factor is calculated based on the quantitative relationship of the mentioned factors The most factors influencing on powder factor is blasting index and - Blasting index is specified by the standard powder factor q0 then the size of blasted rock is a linear distributed) Software by the author can help to classify the blasted rock by blasting index in different in limestone quarries - Required fragment size in the limestone quarries can be calculated under different technical condition (by the formular of Prof Kutuzov, in which Dcp is depended on the crushing and screening conditions) Conditions of the limestone quarries in Vietnam the suitable explosives is ANFO (Explosives produced by Vietnam) The conversion coefficient is calculated by the energy index of the detonation to the ANFO explosive energy The technical powder factor (qcn), which is defined by the required fragment size (dtb) and the fracture block in the rock mass (dmax), is the basis to define the powder factor of any condition There is a linear relation between qcn and dtb (qcn = adtb + b) The appropriate powder factor in limestone quarries is defined by theoretical and experimental measure, based on the technical powder factor qcn Some factors, such as the strength, the fracture, the density, fragment size, are set in the technical powder factor as fluctuation factors; the others are mentioned constant factors From the suggested formular of the powder factor, other blasting parameters and blasting log can be solved in the software that the author mentioned in the dissertation PUBLICATIONS Nguyen Dinh An (2004), Determination of reasonable powder factor for surface mining in Vietnam, Proceedings of mining science and technology conference 19th, Hanoi University of Mining and Geology p 37-41 23 24 Nhu Van Bach, Nguyen Dinh An, Nhu Van Phuc (2006) Blasting design for obtaining desired fragmentation at Apatite mine in Lao Cai, Journal of mining and geology in science and technology, Hanoi University of Mining and Geology p 11-14 Nguyen Dinh An, Bui Xuan Nam (2006) Computer simulations of delay blasting, Journal of mining and geology in science and technology, Hanoi University of Mining and Geology p 74-75 Nhu Van Bach, Lê Văn Quyển, Bui Xuan Nam, Nguyen Dinh An, Nhu Van Phuc (2006) Reduce of ground vibration in blasting at Nui Beo surface coal mines Journal of mining and geology in science and technology 14th edition, Hanoi University of Mining and Geology p 58-62 Nguyen Dinh An, Tran Khac Hung (2010) Determination of reasonable powder factor for limestone quarries in Mining industry journal, 5th edition Vietnam mining science and technology association Ha Noi, p 36-38 Nguyen Dinh An, Nhu Van Bach, Tran Quang Hieu, Nhu Van Phuc (2010) Improve blasting efficiency and minimizing bad impacts on environment for Van Xa limestone quarry, Proceedings of mining science and technology conference, Hanoi University of Mining and Geology, p 3-9 Nguyen Dinh An, Tran Quang Hieu, Tran Khac Hung (2011), Methods for determining peak particle velocity of ground vibration caused by blasting in surface mining, Proceedings of national conference in mining science and technology 22th, Vietnam mining science and technology association, p 265 – 269 Nguyễn Duy Thanh, Nguyen Dinh An, Tôn Thatt Hàm, Đinh Ngọc Hung, (2011), Actual status of the exploitation limestones quarries in Thua Thien Hue province, Proceedings of national conference in mining science and technology 22th Vietnam mining science and technology association, Nha Trang – Vietnam, p 229-232 Nguyen Dinh An (2011), Methods of classification of Blastability, Mining industry journal, 6th edition Vietnam mining science and technology association Ha Noi Tr 45-47 10 Nguyen Dinh An, Tran Khac Hung (2011) Reduce of ground vibration in blasting at Nui Beo surface coal mine Proceedings of The International Symposium on Earth Science and Technology 2011, 6-7 December 2011, Kyushu University, Fukuoka, Japan 11 Nguyen Dinh An , Nhu Van Bach, Nguyen Van Sang, Tran Khac Hung, Tran Dinh Bao (2012) Determination of reasonable powder factor for Vietnam limestone quarries The 2nd International Conference on Advances in Mining and Tunneling Hanoi, August 23-25, 2012, Publishing House for Science and Technology, p 350352 (ISBN 978-604-913-081-6) 12 Nhu Van Bach, Nguyen Dinh An, Le Qui Thao (2012) Analyzing the factors affecting to the vibration when blasting with non-electric detonators The 2nd International Conference on Advances in Mining and Tunneling Hanoi, August 23-25, 2012 Publishing House for Science and Technology P 338-340 (ISBN 978-604-913-081-6) 13 Nhu Van Bach, Nguyen Dinh An, Lê Qui Thao, Tran Dinh Bao (2012), Developing technology of large hole drilling diameter for limestone quarries in Vietnam, Proceedings of mining science and technology conference 20th, Hanoi University of Mining and Geology P 141 14 Nhu Van Bach, Nguyen Dinh An, Bui Xuan Nam, Tran Khac Hung (2012), Reduce of ground vibration in blasting is the use of none electric blasting, Journal of mining and geology in science and technology 38th edition, Hanoi University of Mining and Geology p 25 - 28 15 Nhu Van Bach, Nguyen Dinh An, Tran Khac Hung (2012), Selection of initiation point and delay blasting sequence in order to reduce of ground vibration in blasting is the use of none electric blasting, Mining industry journal, 2th edition, Vietnam mining science and technology association, p 19 – 23  ... quarries in Vietnam’’ is very urgent, satisfying practical demands in mining industry in Vietnam 2 Research purposes of dissertation Based on explosives materials made in Vietnam and theory,... Vietnam mining science and technology association, Nha Trang – Vietnam, p 229-232 Nguyen Dinh An (2011), Methods of classification of Blastability, Mining industry journal, 6th edition Vietnam... factor to ensure a proper fragmentation size for limestone quarries in Vietnam, which used for some limestone quarries in Vietnam to improve economic and technical standards of blasting Object and