RESEARCH ON DETERMINING POWDER FACTOR TO ENSURE A PROPER FRAGMENT SIZE FOR LIMESTONE QUARRIES IN VIETNAM

Transcription

1 MINISTRY OF EDUCATION AND TRAINING UNIVERSiTY OF MINING AND GEOLOGY The issertation was complete at: Surface Mining Department, Mining Faculty, University of Mining an Geology nguyen inh AN Science Instructor: 1. GS.TS. Nhu Van Bach, University of Mining an Geology 2. TS. Nguyen Dang Te, VINACONEX Reviewer 1: TSKH Nguyen Thanh Tuan - Vietnam mining science an technology association RESEARCH ON DETERMINING POWDER FACTOR TO ENSURE A PROPER FRAGMENT SIZE FOR LIMESTONE QUARRIES IN VIETNAM Branch: Mining Engineering Coe: Reviewer 2: TS Nguyen Phu Vu - Vietnam mining science an technology association Reviewer 3: TS Nguyen Sy Hoi - Vietnam mining science an technology association The issertation will be efene before the Council of Doctoral issertation assessment help at Hanoi University of Mining an Geology at on 201 SUMMARY OF DOCTORAL DISSERTATION ha noi The issertation can be foun at the National Library in Hanoi or Library University of Mining an Geology

2 1 INTRODUCTION 1. Urgency of subject In mining inustry in general an open pit mining in particular, blasting is an important which influences irectly loaing, haulage an milling phase. Nowaays, there are many achievements in research of blasting theory an blasting material in mining inustry, especially of blasting parameters for improving rock fragmentation efficiency. Power factor is very important in blasting. Explosive cost use to break a volume unit of rock accoring to requirement an blasting mission is calle as power factor. Power factor is a blasting parameter which epens on physical an mechanical characteristic of blasting, size requirement of rock fragmentation, explosive type, blasting technology, other blasting parameters an so on. Some equations of power factor have been applie in Vietnam. However, they are not close to practice in mines ue to factors influencing power factor are etermine not accurately. Accoring to mining experiences from overseas an isavantages of blasting in open pit mines, especially in quarries in Vietnam, research on etermining power factor to ensure a proper egree of rock fragmentation for some quarries in Vietnam is very urgent. Annually, there are millions m 3 of rock blaste an hence, if goo calculation of power factor can be one to ecrease 1 2%, the amount of explosive use will be reuce consierably. Research results will assist mining companies being more active in blasting an improving their business an prouction which contributes to ensure investment efficiency for new technology an more safety for humans an surrouning environment. Therefore, the PhD issertation Research on etermining power factor to ensure a proper fragmentation size for limestone quarries in Vietnam is very urgent, satisfying practical emans in mining inustry in Vietnam Research purposes of issertation Base on explosives materials mae in Vietnam an theory, research works in omestic an from overseas as well as experimental results of research on relations of factors affecting power factor. I propose a metho to etermination of reasonable power factor to ensure a proper fragmentation size for limestone quarries in Vietnam, which use for some limestone quarries in Vietnam to improve economic an technical stanars of blasting. 3. Object an research scope - Research object is etermining power factor to ensure a proper egree 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, power factor an other blasting parameters. - Research on factors affecting power factor. - Research on relation between power factor an explosive egree an egree of rock fragmentation. - Research on etermining power factor to ensure a proper egree of rock fragmentation for quarries in Vietnam. 5. Research methos - General metho, analytical an comparative metho, inheritance metho, statistical an graphic metho. - Theoretical an experimental metho. 6. Scientific an real significance Power factor is an important blasting parameter affecting an relating closely to other blasting parameters. Accurate etermination of blasting parameters plays the ecisive role in quality an efficiency of blasting in mines. Research result is creating a metho to etermine power factor base on a scientific founation an a relation between power factor an impact coefficients, ensuring it is employe favorably in quarry mining.

3 3 Research result can be applie in quarries in Vietnam an guarantee efficiency an reuction of impacts on environment. 7. Theoretical points to efen 1. Power factor is a basic one which plays an important role in blasting in quarries. Impact coefficients of power factor are ivie into two groups: group of variables an group of coefficients. 2. Technical power factor (q cn ) etermine accoring to require egree of rock fragmentation ( tb ) an egree of crack ( max ) is a founation to etermine power factor for any blasting conitions. Relation between q cn và tb is linear. 3. Reasonable power factor in quarry mining is etermine by technical power factor (q cn ) combining theory with experiment base on qualitative relation between power factor an two impact groups. 8. New points of issertation 1. Determining power factor for quarries using explosive mae in Vietnam, millisecon elay non-electric blasting technique an base on require egree of rock fragmentation in quarry mining. 2. Base on relation between power factor an impact coefficients, classification of the impact coefficients is mae by iviing them into two groups which are better in etermining an optimal power factor. 3. Function of power factor is mae accoring to classification of groups of impact coefficients.. The software for esigning blasting report is buil from a proper power factor. 8. Composition of the issertation The issertation inclues more than 15 pages an lots of tables, graphs, figures an references in omestic an from overseas. Generally, except introuction an conclusion part, the issertation composites the following chapters: Chapter 1 - Overview of researches of power factor an other blasting parameters. Chapter 2 - Research on impact factors of power factor. Chapter 3 - Relation between power factor an explosive egree an egree of rock fragmentation Chapter - Research on etermining power factor to ensure a proper egree of rock fragmentation in some quarries in Vietnam. 9. Publications Base on research tren shown in the issertation, I have 15 research works which are publishe in journal of mining inustry an omestic an international conferences. CHAPTER 1: OVERVIEW OF RESEARCHES OF POWDER FACTOR AND OTHER BLASTING PARAMETERS 1.1. OVERVIEW OF BLASTING TECHNOLOGY IN MINING Valuable eposits are often extracte by open pit or unergroun metho in which mostly rock with harness egree of f = 6 1 an 70% of valuable materials are necessary to break into esire size. Currently, rock fragmentation methos are one mainly by blasting using boreholes an small holes ROLES OF POWDER FACTOR IN MINING One of the most funamental stanars use in evaluating efficiency of rock fragmentation is size of blaste rock or egree of rock fragmentation. This egree epens on mining equipment imension (bucket capacity, haulage metho, an milling). Whereas, power factor is a key parameter to etermine the egree of rock fragment. 1.3 SOME DIFINITIONS OF POWDER FACTORS Calculate power factor, q This power factor is use to calculate an for initial esign or carrying out initial blasting in specific conitions accoring to requirements of blasting. Some other authors treat it like power factor Practical power factor, q th This term helps companies improve their management as well as it is a real value which is use in blasting uner the same conition. The reason is that practical power factor only is calculate after finishing blasting an loaing works.

4 Power factor for creating stanar explosion crater, q c Power factor for creating stanar explosion crater is the costs pening in breaking a bank volume unit of rock to create a stanar explosion crater Stanar power factor, q 0 The quality of blasting is evaluate by the size of rock fragmentation. Hence, stanar power factor is the aequate cost spening in breaking a bank volume unit of rock to get require size of rock fragmentation (in stanar explosion conition) Reasonable power factor, q hl Reasonable power factor is the aequate cost spening in a volume unit of rock so that the total cost of all technological phases is minimize. 1.. OVERVIEW OF BLASTING PARAMETERS IN SURFACE MINING There are two types of blasting parameters in open pit mining incluing: parameters of rilling pattern an parameters of explosive charge OVERVIEW OF RESEARCHES ON POWDER FACTOR Relevant researches on power factor inclues as followings: - Metho of etermining power factor accoring to require size of rock fragmentation (Kuznetsov, B.N Kutuzov). - Metho of etermining power factor accoring to power of explosive (I.P.Oxanhit an P.X. Mirônov). - Metho of etermining power factor accoring to stanar power factor (V.V. Rjevxki). - Metho of etermining power factor accoring to the rule of size istribution within blaste rock heap EVALUATION OF RESEARCHES ON POWDER FACTOR Comments about researches publishe on power factor 1. All researches amit that power factor is a funamental parameter which affects irectly the quality of rock fragmentation an cost of mining prouct. 2. Almost researches evaluate accurately about factors in qualitative aspect which affects the etermination of value of power 6 factor. Impact coefficients can be ivie into some groups as followings: Group 1: Factors characterize environment of blasting such as physical an mechanical properties of rock, egree of harness, egree of crack, rock ensity, Group 2: Factors of explosive are use as a stanar. Researches can be choosing Ammonite N o 6 or ANFO to be a stanar explosive epening on explosive prouction inustry, blasting conition an rock properties in each country. Group 3: Researches also are intereste in parameters of blasting pattern, especially in iameter of charge,. Other parameters are amitte only in qualitative aspect an only mollifying with a rational factor in quantitative aspect epening on specific blasting conitions or just accoring to experimental values. Group : In case of control blasting methos such as millisecon elay blasting, ecke charge blasting, high bench blasting an blasting in high pressure, researches often choose an experimental factor to evaluate. Research metho an equation founation go through three steps as followings: Step 1: Doing a research on the theory of relation between power factor an its impact coefficients. Step 2: Carrying out experiments in lab or inustrial experiments to etermine some quantitative values. Step 3: Establishing a specific relation between power factor an relevant coefficients. Besies, factors having a little or no impact will be are experimental values Problems existing in researches on power factor a. Researches o not concern fully features of power properties of explosive in selecting explosives which are use as a stanar in calculating. b. The introuction of millisecon elay blasting metho ( ) an non - electric facility ( ) has been brought a big efficiency in open pit mining. Millisecon elay non-electric blasting

5 7 using moern firing facilities is better than others because of some avantages as followings : - Being able to control the egree of rock fragmentation ue to increase impact time of explosion an crushe control zone on rock. - Being able to wien rilling pattern (ue to create a large free face) an simultaneously, ensure the quality of fragmentation. Hence, it contributes to ecrease rilling cost. - Reucing power factor whereas improving quality of fragmentation. - Being able to increase blasting scale an control groun vibration. - Millisecon elay non-electric blasting improves quality of fragmentation an reuces harmful effects on environment (especially groun vibration). However, scientific founation of efficiency of rock fragmentation of millisecon elay non-electric blasting is researche not comprehensively in Vietnam. c. Rock broken by blasting is a complex environment in which it is non-ientical an isotropic. Explosion process occurs very quickly so that etermining stress state of each point is very ifficult. Using equivalent materials to moel explosion samples an experimental factors to converse it into practical environment in blasting are often make a large error.. Equations establishe are often complicate or contain lots of experimental factors which reuce ability to apply in practice. e. In general, all researches in omestic an from overseas affirm that the egree of rock fragmentation (shown in iameter of grain size) influences consierably power factor. At the moment, there is no research which solves eeply an completely this problem an fixes with practical situation in quarries in Vietnam. Hence, it is able to propose some problems to research next as followings: Establishing a metho to etermine a proper power factor in quarries in Vietnam is base on: Using millisecon elay non-electric blasting metho with explosive mae in Vietnam (ANFO); require egree of rock fragmentation in quarries. 8 CHAPTER 2: RESEARCH ON FACTORS AFFECTING POWDER FACTOR 2.1. REQUIREMENTS OF BLASTING IN QUARRY - Grain size of rock fragmentation must be uniform an oversize rock must be very few. - Dimension of blaste rock heap (height, with) must fix with loaing an haulage equipments in orer to ensure prouction an safety for them an being suitable with parameters of mining metho. - Bench floor must be smooth an limits postpulse an improves capacity factor of rillhole. - Blasting activity must ensure strict safety for humans, houses an builings uner the effect of groun vibration, air blast an flying rock FACTORS AFFECTING POWDER FACTOR - Factors are feature for environment which blast activity takes place. - Economic an technical factors inclue blasting parameters, type of explosive being use, an firing metho COMMENTS AND EVALUATION OF RELATION BETWEEN POWDER FACTOR AND IMPACT COEFFICIENTS Coefficients affecting power factor can be ivie into two groups: Group of variables inclues coefficients that affect irectly an change power factor continuously. They are: + Chemical an physical properties of rock inclue harness factor f an egree of crack. + Require egree of rock fragment that is grain size of blaste heap rock an characterize by average size of rock. Group of coefficients inclues factors which influence power factor in a certain level, epening on explosion conition, as followings: + Type of explosive + Metho of firing control + Technology an technique of carrying out blasting.

6 9 CHAPTER 3: RELATION BETWEEN POWDER FACTOR AND ROCK BLASTABILITY AND DEGREE OF ROCK FRAGMENTATION 3.1. RELATION BETWEEN POWDER FACTOR AND DEGREE OF EXPLOSION Blasting consiers rock as a main object to impact. Degree of explosion characterizes how ifficult to fire explosive are an is etermine by power factor uner a stanar conition. The larger power factor is, the higher egree of explosion is an vice versa ROCK CLASSIFICATION IN MINING Classification of rock plays an important role in mining. It is base on selection of rilling machine, metho of firing, mining prouction norm an cost of blasting material Founation of rock classification Founation of rock classification accoring to egree of explosion is power factor q o. Base on this factor, grain size of blaste rock heap istributes as a line on graph. Metho of etermination of q o is as follows: experiment of blasting using two type of power factor q 1 an q 2 is one two times for each type of rock an then etermining property of grain size istribution with size x x 0 ( P 1 an P 2 ) corresponing to two courses of blasting. Finally, q 0 is etermine as followings: q 0 2 =, kg/m 3 (3.1) X 0 ( q q ) lg 2 q q P1 lg P L max Where: P 1, P 2 are percentages of grain size corresponing to x x 0 in two courses of blasting q 1 và q 2, respectively Result of rock classification of blastability for some limestone quarries in Vietnam This metho was applie for experiment in some limestone quarries such as Ninh Dan Thanh Ba Phu Tho limestone quarry (owne by Song Thao cement company), Van Xa Thua Thien Hue limestone quarry (owne by LUKS Vietnam cement company), Thuong Tan IV Binh Duong limeston quarry. Quarries use 10 blasthole with iameter in mm, bench height in 7 15m, bucket capacity in 2 5 m 3, millisecon elay non-electric blasting metho (with non-electric facility), AD-1 explosive, ratio of oversize rock in heap less than 2 3%. Accoring to experimental blasting an 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 q 0 < 0,3 Easy q 0 = 0,31 0,38 Average Very q 0 = 0, Difficult q 0 = 0,7 0,55: ifficult q 0 > 0,56 Extreme ifficult Designing a software to rock classify of blastability Fig 3.1- Block iagram for etermining stanar power factor Fig 3.2- Interface of software use to etermine rock classification of blastability 3.3. RELATION BETWEEN POWDER FACTOR AND DEGREE OF ROCK FRAGMENTATION In orer to evaluate efficiency of fragmentation, egree of lump (D tb )is use. In case of the same blasting conition, the larger power factor is the smaller (D tb )is. Optimum requirement of grain size within blaste rock heap epens on mining equipment fleet (bucket capacity, metho of haulage).

7 Proper egree of rock fragmentation General efinition of egree of rock fragmentation Accoring to international researches, largest size of blaste rock is etermine by loaing equipment as follow: D cp = ( 0,7 0,8) 3 E, m (3.2) Where :D cp maximum size of blaste rock, m; E bucket capacity, m 3. Maximum size of blaste rock base on milling conition is etermine as follow: D cp = (0,7 0,8)B, m (3.3) Where : B- minimum size of bin gate, m. Degree of rock fragmentation is etermine by iameter of grain size within blaste heap as follow: id i D tb = γ (3.) 100 Where: D i average size of grain size of i ; γi - percentage of grain size of i, % Determining egree of rock fragmentation Degree of rock fragmentation can be etermine by methos as followings: - Determining average size of blaste rock D tb by statistical power metho. - Determining average fragment size of blaste rock D tb by semiexperimental metho of V.M. Kuzonhetxov. - Determining average fragment size of blaste rock D tb accoring to metho of B.N. Kutuzov. - Determining average fragment size of blaste rock D tb average metho from evaluating size of blaste rock in practice Evaluation of egree of rock fragmentation - Degree of rock fragmentation is reasonable if it ensures that total cost of a prouction unit in mining is minimum. n i= 1 n Ci + E K i i= 1 min ; (3.5) Where: C i prouction unit of one m 3 of rock accoring to phases incluing: primary blasting an rilling; loaing, hauling an overisize rock breaking đ/m 3 ; K i basic cost of one m 3 of rock 12 accoring to phases incluing: rilling; loaing, hauling an milling, đ/m 3 ; E coefficient of investment efficiency Proper egree of rock fragmentation for quarries In orer to etermine a proper egree of rock fragmentation accoring to technical conitions of quarries, it is possible to use some metho as followings: - Accoring to bucket capacity: 3 tb = (0,15 0,2) E (3.6) Where: E bucket capacity, m 3 - Determining average size of blaste rock accoring to metho of B.N. Kutuzov Dcp Dtb = (3.7) 3 Vqc 1 V o Where : V qc percentage of size of blaste rock, %; V o percentage of natural cracking mass in bank being larger than require size of blaste rock. Accoring to statistical an analytical result of ata from quarries in Vietnam, application of equation (3.7) is suitable to etermine egree of rock fragmentation. Here, require size of blaste rock D cp is etermine base on milling conition. Maximum size of blaste rock epens on type an capacity of milling machine. CHAPTER : DETERMINATION OF REASONABLE POWDER FACTOR FOR LIMESTONE QUARRIES IN VIETNAM.1. Research to the relationship between power factor with element affect. Determination of reasonable power factor for limestone quaries in Vietnam to have research to relationship between power factor with affecting element to blasting Research to relationship between power factor with explosives

8 13 For the selection explosives base on: - The first is characteristic of explosives - The secon is the cost of explosives When etermining power factor by using other explosives, it is ifferent from stanar explosives must mention the conversion coefficient because the explosive energy is ifferent.1.2. Research to relationship between power factor with rock properties Accoring to experimental an theory of blasting, the rock properties is the most important an irectly affect to calculate power factor Research to relationship between power factor with blasting parameters Relationship between power factor with charge iameter Definition of charge iameter that irectly affect to Fragmentation size an cost of prouct. However with the require of Fragmentation size shoul be increasing charge iameter because the large iameter overcome high bench an then extening rilling patterns, to reuce cost of rilling Relationship between power factor with hole spacing Through results research about the relationship level of power factor with blasting parameters as charge iameter, bench high, hole spacing are little change, because there are epen on blasting requirements..1.. Relationship between power factor with blasting methos When calculating power factor, blasting metho is not the number variables of function power factor, which is the only coefficient epens on blasting conitions The relationship for the etermination of Power factor - Fragmentation size This is important factor for etermination of reasonable power factor. Accoring to experimental an theory of blasting can confirm this relationship is linear function, it means: q = ϕ ( tb ) = a tb + b (.1) The relationship for the etermination of Power factor - environment To protect the environment when blasting in limestone quarries as follows: - Using suitable types of explosives Fig.1- Power factor epen - Using suitable power factor on Fragmentation size - Using appropriate blasting parameters - Using reasonable blasting methos.2. DETERMINATION OF REASONABLE POWDER FACTOR FOR LIMESTONE QUARRIES IN VIETNAM.2.1. Analysis, assessment an classification of the elements affecting to power factor Power factor epens on rock properties, explosive types, blasting methos, blasting parameters, an require fragmentation. The influence of each factor to power factor is ifferent, base on these properties it can be ivie into two groups. Group one: The factors irectly influencing to reasonable power factors: - Rock properties, (rock strength, rock fracture); - Require fragmentation, (average fragment size); These factors are variables of the function of reasonable power factors Group two: The factors inirectly influencing to reasonable Fig 2- Outline of illustrations function of power factor an affecting factors x 1, x 2 - The variables; k 1, k2- the affecting factors

9 15 power factors, it means that the values of power factor change in certain range. The power factor is a function Y, the affecting factors are variables x 1, x 2,... May be function of power factor such as: Y = f(x 1, x 2,.) (.2).2.2. Definition of optimum explosives Base on the requirements an characteristics of limestones quarries in Vietnam, using stanar explosives are ANFO to calculation.2.3. Metho of etermination of power factor for limestone quarries Power factor epens on blasting requirements The research results inicate the istribution law of particle size an the function of power factor with average fragment size is linear function: q cn = a tb + b (.3) Where- q cn is technical power factor, kg/m 3 ; tb is average fragment size, m; a, b is empirical coefficients, it foun from empirical blasts. For etermination 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 harness equal 6 12, egree of fracturing belong to level II III, IV; - After each blast carrie out photographe an monitoring muck loaing. Use Autoca và Spit Desktop software for etermination fragment size (Fig.3). The results of etermination fragment size shown on table.1 an graph of fragment size istribution shown on fig.. Table.1: The results of etermination fragment size 16 Fig.3- interfaces software of Spit Desktop - From the results of blasting test at limestones quarries, we buile the functional relationship between the average fragment size with power factor is shown on fig.5,.6,.7. Fig.- Graph of fragment size istribution Fig.5- Power factor - Fragmentation size relationship at Ninh Dan limestone quarry Fig.6- Power factor - Fragmentation size relationship at Thuong Tan IV limestone quarry Fig.7- Power factor - Fragmentation size relationship at Yen Dunyen limestone quarry

10 17 Base on results blasting test, if other affecting factor is not changing as rock harness, type of explosives, fracturing,.. then only changing fragment size, to realize: - When tb 0 then q cn = q max = b - When q cn = 0 0 = a max + b max = b a b a = max Where: max Diameter of meium fracture block in the rock mass Equation (.2) then is becomes: q b cn = tb + max b (.) - Accoring to the statistics from blasting at limestone quarries, maximum of power factor (q max ) equal 0,8 kg/m 3. Then q cn = q max = 0,8kg/m 3 b = 0,8, The equation (.3) becomes: q tb = 0,8 0,8 (.5) cn + max Power factor epens on rock harness f The rock strength is estimate by harness coefficient f, (M.M. Protoiaconov's classification). When harness coefficient increasing, Power factor also increasing. When mentioning the harness coefficient, the formula of Power factor is etermine as follows: q 1 = k 1.q cn (.6) Accoring to the statistics, blasting test etermination relationship between rock harness power factor q cn an q 1 shown on table.2 Table.2: Relationship between rock harness power factor q cn an q 1 Rock harness (f) Technical power factor q cn, (kg/m 3 0,25 0,28 0,32 0,35 0,0 0,5 0,8 ) Power factor q 1, 0,30 0,35 0,39 0,6 0,53 0,58 (kg/m 3 0,25 ) q 1 /q cn 1 1,07 1,10 1,13 1,16 1,18 1,21 18 From ata in table 2 etermine the relationship between quotient q 1 /q cn an rock harness such as: q 1 /q cn = 0,635.f 0,262 (.7) Where q 1 /q cn is harness coefficient. This is coefficient k 1 nee to fin. The equation (.6) becomes: k = (.8) 1 0,635 f The power factor can be etermine by the following formula q = (.9) 1 k1 qcn = 0,635 f qcn Power factor epens on rock ensity When mentioning the rock ensity, the power factor can be etermine by the following formula. q 2 = k 2.q 1 (.10) For the limestons quarries in Vietnam, average rock ensity is 2,6 t/m 3. Accoring to the theory of blasting an blasting test coefficient k 2 etermine by the following formula: γđ k = 2 2,6 (.11) Replace (.10) in (.9) an equation (.9) then is becomes: γđ q = 0,635 f q 2 cn 2,6 (.12) Power factor epens on type of explosives When mentioning the type of explosives. Using coefficient k 3 is relative heat of explosives: k 3 = Q tc /Q (.13) Where: Q- heat of explosives using, Kcal/kg; Q tc - heat of stanar explosives ANFO. Power factor can be etermine by the following formula: γđ q = k 0,635 f q (.1) 3 3 cn 2,6

11 Power factor epens on blasting metho Toay, the elay initiation metho is use in all of the limestone quarries in Vietnam because of its many avantages. The most common value of k when using elay initiation metho will generally lie in the range of 0.85 to Power factor can be etermine by the following formula: γđ q 3 = k k 3 0,635 f q (.15) cn 2, Power factor - blasting parameters an environment relationship The relationship between power factor - blasting parameter an environment is inirectly. Metho of etermination of reasonable power factor (q hl, kg/m 3 ) oes not take into account this relationship an also not shown in this formula. From the results of the formulas (..1) to establish the final formula of etermination of reasonable power factor is becomes: tb γđ q hl = 0,653 f ( 0,8 + 0,8) k 3 k, kg/m 3 (.16) 2,6 max The formula etermination of reasonable power factor shows full factors of influence on power factor an meets the requirement an purposes of the blast as when changing fragment size, rock property, explosives type an conition 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 nee to be more multiple blasting experimental to etermine exactly influence coefficient..3. Buil program calculates power factor, blasting parameters an blasting patterns From the stuy, author have built the software calculates power factor, blasting parameters an blasting patterns. Programs written by 20 VBA / Excel language help engineers easy to use for calculating blasting parameters, blast log quickly, exactly an reliably Software structure Software incluing parts: - Part 1: General Information - Part 2: Determination of reasonable power factor - Part 3: Determination of blasting parameters - Part : Drawing blasting patterns.3.2. Introuce some interfaces an results calculate by the software Fig.8- Block Diagram of software Fig.9- General Information Fig.10- Determination of reasonable power factor Fig.11- Drawing blasting patterns

12 ÐKN Fig-.12- Delay blasting patterns using non electric etonation 00 Fig-.1. Interfaces of blast log GENERAL CONCLUSION Fig-.13- Delay blasting patterns using electric blasting cap 1. Rock blasting is the first step in mining, especially in limestone quarries. One of the most important blasting parameters nees caring is power factor. This parameter has consierable influence on other blasting parameters an the environmental impacts. 2. There are various natural an technological factors that influence on the power factor. Two groups classify the elements: fluctuation factors an constant factors. In ifferent conition, the. 22 power factor is calculate base on the quantitative relationship of the mentione factors. 3. The most factors influencing on power factor is blasting inex an - Blasting inex is specifie by the stanar power factor q 0. then the size of blaste rock is a linear istribute). Software by the author can help to classify the blaste rock by blasting inex in ifferent in limestone quarries. - Require fragment size in the limestone quarries can be calculate uner ifferent technical conition (by the formular of Prof. Kutuzov, in which D cp is epene on the crushing an screening conitions).. Conitions of the limestone quarries in Vietnam the suitable explosives is ANFO (Explosives prouce by Vietnam). The conversion coefficient is calculate by the energy inex of the etonation to the ANFO explosive energy. 5. The technical power factor (q cn ), which is efine by the require fragment size ( tb ) an the fracture block in the rock mass ( max ), is the basis to efine the power factor of any conition. There is a linear relation between q cn an tb (q cn = a tb + b). 6. The appropriate power factor in limestone quarries is efine by theoretical an experimental measure, base on the technical power factor q cn. Some factors, such as the strength, the fracture, the ensity, fragment size, are set in the technical power factor as fluctuation factors; the others are mentione constant factors. 7. From the suggeste formular of the power factor, other blasting parameters an blasting log can be solve in the software that the author mentione in the issertation. PUBLICATIONS 1. Nguyen Dinh An (200), Determination of reasonable power factor for surface mining in Vietnam, Proceeings of mining science an technology conference 19 th, Hanoi University of Mining an Geology. p 37-1.

13 23 2. Nhu Van Bach, Nguyen Dinh An, Nhu Van Phuc (2006). Blasting esign for obtaining esire fragmentation at Apatite mine in Lao Cai, Journal of mining an geology in science an technology, Hanoi University of Mining an Geology. p Nguyen Dinh An, Bui Xuan Nam (2006). Computer simulations of elay blasting, Journal of mining an geology in science an technology, Hanoi University of Mining an Geology. p Nhu Van Bach, Lê Văn Quyển, Bui Xuan Nam, Nguyen Dinh An, Nhu Van Phuc (2006). Reuce of groun vibration in blasting at Nui Beo surface coal mines. Journal of mining an geology in science an technology 1th eition, Hanoi University of Mining an Geology. p Nguyen Dinh An, Tran Khac Hung (2010). Determination of reasonable power factor for limestone quarries in. Mining inustry journal, 5th eition. Vietnam mining science an technology association. Ha Noi, p Nguyen Dinh An, Nhu Van Bach, Tran Quang Hieu, Nhu Van Phuc (2010). Improve blasting efficiency an minimizing ba impacts on environment for Van Xa limestone quarry, Proceeings of mining science an technology conference, Hanoi University of Mining an Geology, p Nguyen Dinh An, Tran Quang Hieu, Tran Khac Hung (2011), Methos for etermining peak particle velocity of groun vibration cause by blasting in surface mining, Proceeings of national conference in mining science an technology 22 th, Vietnam mining science an technology association, p 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, Proceeings of national conference in mining science an technology 22 th. Vietnam mining science an technology association, Nha Trang Vietnam, p Nguyen Dinh An (2011), Methos of classification of Blastability, Mining inustry journal, 6th eition. Vietnam mining science an technology association. Ha Noi. Tr Nguyen Dinh An, Tran Khac Hung (2011). Reuce of groun vibration in blasting at Nui Beo surface coal mine. Proceeings of The International Symposium on Earth Science an 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 power factor for Vietnam limestone quarries. The 2n International Conference on Avances in Mining an Tunneling. Hanoi, August 23-25, 2012, Publishing House for Science an Technology, p (ISBN ). 12. Nhu Van Bach, Nguyen Dinh An, Le Qui Thao (2012). Analyzing the factors affecting to the vibration when blasting with non-electric etonators. The 2n International Conference on Avances in Mining an Tunneling. Hanoi, August 23-25, Publishing House for Science an Technology. P (ISBN ). 13. Nhu Van Bach, Nguyen Dinh An, Lê Qui Thao, Tran Dinh Bao (2012), Developing technology of large hole rilling iameter for limestone quarries in Vietnam, Proceeings of mining science an technology conference 20 th, Hanoi University of Mining an Geology. P Nhu Van Bach, Nguyen Dinh An, Bui Xuan Nam, Tran Khac Hung (2012), Reuce of groun vibration in blasting is the use of none electric blasting, Journal of mining an geology in science an technology 38 th eition, Hanoi University of Mining an Geology. p Nhu Van Bach, Nguyen Dinh An, Tran Khac Hung (2012), Selection of initiation point an elay blasting sequence in orer to reuce of groun vibration in blasting is the use of none electric blasting, Mining inustry journal, 2th eition, Vietnam mining science an technology association, p