Wyniki wyszukiwania - BazTech

1

Method and tool for drilling and explosion well expansion in hard rocks

Antonchik Volodymyr, Hankevich Valentyn, Minieiev Sergyi, Pashchenko Oleksandr, Buketov Valentyn

Mining Machines

|

2023

|

vol. 41, iss. 3

158--167

EN

The paper represents the problem of expanding wells in hard and especially hard rocks. The general direction of solving this problem, theprevious methods of solving it and their shortcomings are shown. Anew method of drilling and blasting expansion of wells in strong and especially hard rocks is presented, using the energy of a directed explosion of low power to create a three-dimensional network of cracks in the rock mass around the well. The drawings ofthe tool for drilling and blasting expansion of wells in strong and especially hard rocks at the level of a draft design are given, and the calculation of the explosion energy of a single charge of explosives is carried out, and their mass necessary for such an explosion is determined.

2

Influence of explosive maximum instantaneous charge on blasting environmental impact

Odeyemi Olukemi Y., Taiwo Blessing O., Alaba Olarewaju C.

Journal of Sustainable Mining

|

2023

|

Vol. 22. iss. 4

344--357

EN

Our research looked at the effect of explosive maximum instantaneous charge on ground vibrations and noise levels during blasting operations at the Calaba limestone quarry in Nigeria. Vibrock (V9000) seismograph was used to take readings related to ground vibrations and noise generated during all blasting operations that took place in the quarry for a period of one year. The results obtained indicate that the average ground vibration readings fall between 0.25 mm/s to 3.6 mm/s and the average noise decibel generated during the blasting operations between 35 and 158 dB. An artificial neural network (ANN) model is developed in this study for the prediction of blast-induced ground vibration and noise level. The proposed ANN model was compared with existing empirical models and was found to give the highest prediction accuracy. It was revealed that both noises generated and ground vibrations during all blasting operations increase with an increase in explosive maximum instantaneous charge. Additionally, the measuring equipment distance from the blast site was also revealed to have a negative correlation with noise generated and ground vibrations.

3

Simulation on Flyrock due to Blasting Using Smoothed Particle Hydrodynamics (SPH) with LS-Dyna software

Dinh Bao Tran, Van Trieu Do, Van Viet Pham, An Nguyen Dinh

Inżynieria Mineralna

|

2023

|

no. 2, vol. 1

13--21

EN

In surface mining operation, blasting method has been commonly used and accounted highly for breaking waste rock and mineral. The main goal of the activity is fundamental fragmentation by energy generation due to blasting. However, only 20% to 30% blasting energy is generated to fragment rock. The remain energry is wasted for flyrock, ground vibration, air overpressure, dust and too fine fragmentation. Flyrock in blasting is large risk for surface mines and occupies more than a half of incidents relating to blasting at surface mines, because this is a severe issue and causes negative reaction of the surrounding residients. However, studies on flyrock-phenomenon prediction methods for blasting in Vietnam have been also limited. In the study, simulation analysis method on induce-blasting-induced flyrock experiment using Smoothed Particle Hydrodynamics (SPH) with LS-Dyna software. Two-dimension modelling was built and practically applied for B2 cross section of Mong Son quarry in Yen Bai province. The result showed that the ability of Smoothed Particle Hydrodynamics (SPH) in analysizing flyrock trajectory distance in blasting. By using the modelling with field-site parameters, the researcher monitored flyrock velocity at installed time periods, such as 1.5 second when the flyrocks fly with a maximum distance of 85 m from blasting site and their average velocity of 40 m/s.

4

Occupational Risk Management Method for Quarry Blasting Operations Based on Modified FMECA Algorithm

Dworzak Michał

Inżynieria Mineralna

|

2023

|

no. 1

241--249

EN

Occupational risk assessment is one of the most crucial legal obligation for employers and the basis of accident prevention. In the case of highly repetitive work operations and an almost constant work environment, performing a preliminary risk analysis and checking risk levels periodically may be sufficient. In the case of blasting operations in quarries: the mining and geological conditions, technology, blasting methods, explosives, and initiating agents are variables that affect occupational safety. Moreover they make occupational risk assessment difficult to apply on the operational level. Therefore, occupational risk management followed by a deep analysis of hazards and their associated risks may allow to design and manage blasting works with regard to occupational risk. The paper presents the method for the support of occupational risk management in quarry blasting operations based on a modified FMECA algorithm. The designed method provides a systematic approach to risk identification, and allows to indication of the main occupational hazards that should be prioritized for preventive action. The preventive action which could be implied in the design stage by changes in technology or work organization based on options available for a particular quarry.

PL

Ocena ryzyka zawodowego stanowi jedno z podstawowych wymagań prawnych stawianych pracodawcy oraz fundament prewencji wypadkowej. W przypadku prac charakteryzujących się powtarzalnymi czynnościami i niewielką zmiennością środowiska pracy, wykonanie oceny ryzyka zawodowego wraz z okresową kontrolą poziomu ryzyka wydaje się wystarczające i spełnia wymaganie stawiane przez prawo. Rozważając prace strzałowe w kamieniołomach, warunki górnicze i geologiczne, stosowana technologia i metody strzelania, środki strzałowe i inicjujące są zmiennymi, które mogą wpływać na poziom bezpieczeństwa pracy. Ponadto zmienne występujące w trakcie robót strzałowych powodują, że ocena ryzyka zawodowego i jej wyniki są trudne do wdrożenia na poziomie operacyjnym. Rozwiązaniem tego problemu może być zarządzanie ryzykiem zawodowym poprzedzone szczegółową analizą zagrożeń i towarzyszących im ryzyk, które może pozwolić na projektowanie i zarządzanie robotami strzałowymi z uwzględnieniem ryzyka zawodowego pracowników. Artykuł prezentuje metodę wspierającą zarządzanie ryzykiem zawodowym w robotach strzałowych w odkrywkowym górnictwie skalnym opartą na zmodyfikowanym algorytmie FMECA. Zaproponowana metoda pozwala na systematyczne podejście do identyfikowania ryzyk zawodowych i wskazuje na kluczowe zagrożenia zawodowe, dla których powinny zostać w szczególności zastosowane działania profilaktyczne. Ograniczenie ryzyka zawodowego może być osiągnięte na etapie projektowania robót strzałowych poprzez zmianę technologii lub organizacji pracy w oparciu o dostępne możliwości dla danego zakładu górniczego, a wybór charakteru rodzaju zmian jest wspierany przez zaproponowany w niniejszym artykule algorytm.

5

Study of rock fracture under blast loading

Baranowski Paweł, Kucewicz Michał, Pytlik Mateusz, Małachowski Jerzy

Bulletin of the Polish Academy of Sciences. Technical Sciences

|

2022

|

Vol. 70, nr 5

art. no. e141723

EN

A study of dolomite rock material failure using a simple small-scale blast setup is presented. Laboratory tests were conducted using disc specimens drilled with a borehole in the center. A detonation cord and a blasting cap were fitted inside the borehole to induce cracking and fracturing of the specimens. The specimens were inserted between two steel plates, which were compressed against the specimen using bolt screws. Prior to testing, the most suitable screw torque for constraining the vertical displacement of the specimen surfaces without compressing the specimen was selected based on numerical simulations. Then, the experimental tests with the blasting cap were simulated using the Johnson–Holmquist II (JH-2) material model, and the properties of the blasting cap were determined and verified in two special tests with a lead specimen. Possessing the validated model, the influence of specimen thickness on the cracking patterns was finally analyzed. This paper presents a relatively easy method for studying rock material behavior under blast loading and for validating the numerical and constitutive models used for rock simulations.

6

Prediction of backbreak in the blasting operations using artificial neural network (ANN) model and statistical models (case study: Gol-e-Gohar iron ore mine No. 1)

Sirjani Abbas Khajouei, Sereshki Ferhang, Ataei Mohammad, Hosseini Mohammad Amir

Archives of Mining Sciences

|

2022

|

Vol. 67, no. 1

107--121

EN

Backbreak is an undesirable phenomenon in blasting operations, which can bedefined as the undesirable destruction of rock behind the last row of explosive holes. To prevent and reduce its adverse effects, it is necessary to accurately predict backbreak in the blasting process. For this purpose, the data obtained from 66 blasting operations in Gol-e-Gohar iron ore mine No. 1 considering blast pattern design Parameters and geologic were collected. The Pearson correlation results showed that the parameters of the hole height, burden, spacing, specific powder, number of holes, and the uniaxial compressive strength had a significant effect on the backbreak. In this study, a multilayer perceptron artificial neural network with the 6-12-1 architecture and six multiple linear and nonlinear statistical models were used to predict the backbreakin the blasting operations. The results of this study demonstrated that the prediction rate of backbreak using the artificial neural network model with R2 = 0.798 and the rates of MAD, MSE, RMSE and, MAPE were0.79, 0.93, 0.97 and, 11.63, respectively, showed fewer minor error compared to statistical models. Based on the sensitivity analysis results, the most important parameters affecting the backbreak, including the hole height, distance between the holes in the same row, the row spacing of the holes, had the most significant effect on the backbreak, and the uniaxial compressive strength showed the lowest impact on it.

7

Oznaczanie prędkości detonacji materiałów wybuchowych oraz czasów opóźnień zapalników w długich otworach strzałowych

Mertuszka Piotr, Szumny Marcin, Fuławka Krzysztof, Żołądek Tomasz, Rink Patrycja

Przegląd Górniczy

|

2021

|

T. 77, nr 1-3

21--29

PL

W artykule przedstawione zostały wyniki pilotażowych pomiarów prędkości detonacji materiałów wybuchowych oraz dokładności opóźnień zapalników w warunkach in situ z wykorzystaniem wielokanałowego rejestratora DataTrap II. Pomiary prowadzono w długich otworach strzałowych w kopalni odkrywkowej surowców skalnych. Dzięki zastosowaniu metody ciągłej możliwe było określenie zmian prędkości detonacji na całej długości kolumny materiału wybuchowego z jednoczesnym określeniem dokładności opóźnień stosowanych zapalników nieelektrycznych i elektronicznych.

EN

The article presents the results of pilot measurements of detonation velocity and detonators’ delays accuracy under the in-situ conditions using the multichannel DataTrap II recorder. Tests were carried out in long blastholes in an open-pit mine. The applied continuous method allowed to determine the changes in the detonation velocity along with the entire length of the explosive column and measure the delay accuracy of electronic and non-electric detonators.

8

Estimation of air overpressure using bat algorithm

Dehghani Hesam, Ali Mohammad Nia Farid

Mining Science

|

2021

|

Vol. 28

77-92

EN

Air overpressure (AOp) is an undesirable phenomenon in blasting operations. Due to high potential to cause damage to nearby structures and to cause injuries, to personnel or animals, AOp is one of the most dangerous adverse effect of blasting. For controlling and decreasing the effect of this phenomenon, it is necessary to predict it. Because of multiplicity of effective parameters and complexity of interactions among these parameters, empirical methods may not be fully appropriate for AOp estimation. The scope of this study is to predict AOp induced by blasting through a novel approach based on the bat algorithm. For this purpose, the parameters of 62 blasting operations were accurately recorded and AOp were measured for each operation. In the next stage, a new empirical predictor was developed to predict AOp. The results clearly showed the superiority of the proposed bat algorithm model in comparison with the empirical approaches.

9

Determining the timing accuracy of electronic detonators using different methods

Pytlik Mateusz, Mertuszka Piotr

Materiały Wysokoenergetyczne

|

2021

|

T. 13

143--156

EN

The timing accuracy of detonators used in the mining industry has a significant influence on the safety and effectiveness of blasting operations. However, the accuracy of the time delays in electric and non-electric detonators is unpredictable and may differ from the intended timing due to the pyrotechnic delay element. The latest generation of electronic detonators provide a very high precision of firing compared to pyrotechnic ones. Different methods may be used to determine a detonator’s delay accuracy. Selected methods were evaluated in order to identify the most appropriate one for electronic blasting cap testing. The research involved an electroacoustic sensor, an amplifier with an open-circuit probe, a high-speed camera and a data recorder.

PL

Dokładności opóźnień zapalników stosowanych w przemyśle górniczym mają istotny wpływ na bezpieczeństwo i efektywność robót strzałowych. Tymczasem, dokładność opóźnień zapalników elektrycznych i nieelektrycznych jest nieprzewidywalna i może różnić się od zamierzonego czasu z uwagi na pirotechniczny element opóźniający. Zapalniki elektroniczne najnowszej generacji pozwalają na bardzo dużą precyzję odpalania w odniesieniu do zapalników pirotechnicznych. Do oznaczania dokładności opóźnień zapalników stosuje się różnego rodzaju metody. W ramach artykułu przeprowadzono ocenę niektórych metod oznaczania dokładności opóźnień zapalników, co miało na celu wskazanie metody najbardziej odpowiedniej do badań zapalników elektronicznych. Badania obejmowały czujnik elektroakustyczny, wzmacniacz pomiarowy z sondą rozwarciową, szybką kamerę i rejestrator danych.

10

Wpływ budowy geologicznej skał na projekt robót strzałowych. Cz. II

Grześkowiak Arkadiusz

Kruszywa : produkcja - transport - zastosowanie

|

2021

|

Nr 3

56--62

PL

W artykule przedstawiono główne problemy związane z identyfikacją właściwości skał przeznaczonych do urabiania za pomocą materiałów wybuchowych. Wskazano metody badań właściwości skał oraz ich zastosowanie w projektowaniu robót strzałowych, a także możliwe skutki wynikające z ich nieprawidłowej oceny. Opisano także sposoby weryfikacji wstępnych parametrów budowy na podstawie robót wiertniczych i możliwości wykorzystania dostępnych informacji do poprawy uzyskiwanych efektów strzelania.

EN

The article presents main problems related to identifying the properties of rocks intended for mining with explosives. Methods of determining rock properties and their application in blast design are indicated, as well as possible effects resulting from their incorrect evaluation. Methods of verifying initial geological structures parameters based on drilling works and possibilities of using available information to improve blasting effects are also described.

11

Wpływ budowy gelogicznej skał na projekt robót strzałowych. Cz. I

Grześkowiak Arkadiusz

Kruszywa : produkcja - transport - zastosowanie

|

2021

|

Nr 2

52--57

PL

W artykule przedstawiono główne problemy związane identyfikacją właściwości skał przeznaczonych do urabiania za pomocą materiałów wybuchowych.

EN

The article presents main problems related to identifying the properties of rocks intended for mining with explosives. Methods of determining rock properties and their application in blast design are indicated, as well as possible effects resulting from their incorrect evaluation. Methods of verifying initial geological structures parameters based on drilling works and possibilities of using available information to improve blasting effects are also described.

12

Study of the Influence of Sensitizer Content on the Density of a Bulk Emulsion Explosive Used in Underground Operations

Kramarczyk Bartłomiej, Mertuszka Piotr

Central European Journal of Energetic Materials

|

2021

|

Vol. 18, no. 4

429--447

EN

Emulsion matrix sensitization is typically performed by chemical reduction of the density using different sensitization agents. Mixing of the components takes place directly inside the loading hose, which is equipped with static mixing devices. Precise dosing of the components, due to the multi-ingredient nature of the mixture, has a significant impact on the detonation and operational parameters of the end product. However, the operation and maintenance of the mixing-charging units in underground mines is very difficult due to the local conditions. As a consequence, different values for the detonation parameters may be expected when charging the same explosive into blastholes using two different charging units. The present article presents the results of laboratory testing of the influence of the sensitizing agent content on the density of a bulk emulsion explosive. Analysis confirmed that increasing the concentration of the sensitizing agent by 30% and 50% led to density reductions by 4% and 7%, respectively. In turn, reducing the sensitizer content by the same percentages resulted in an increase in the final density by 7% and 8%, respectively.

13

Analysis of positive elevation effect and prediction of vibration velocity of bench blasting vibration

Zhang X. J., An H. M.

Archives of Civil Engineering

|

2021

|

Vol. 67, nr 1

599--618

EN

Accurate prediction of blasting vibration should be achieved in mine blasting production practice. It is also a critical problem in the field of blasting vibration control technology research. In this research paper, on the basis of the previous research results and taking account into the reflection principle of elastic wave at the free interface, the authours proposes the blasting seismic wave propagation model. In addition, the blasting positive elevation effect are theoretically explained in detail, and the vibration velocity prediction formula of the positive elevation effect is derived. Finally, the positive elevation effect mechanism and the step (positive) formula are calibrated based on the on-site monitoring data of blasting vibration of Qipanjing Jinou coal mine. In beirf, a theoretical basis is laid by this paper for similar blasting projects.

14

Współczesne pneumatyczne kabinowe oczyszczarki strumieniowo-ścierne. Część II

Woźniak Kazimierz

Obróbka Metalu

|

2020

|

nr 3

26--33

PL

W pierwszej części opracowania (OM 3/19) przedstawiono zasady działania pneumatycznych oczyszczarek kabinowych, natomiast w tej części zaprezentowano przykłady rozwiązań konstrukcyjnych tych obrabiarek, które umożliwiają realizowanie obróbki strumieniowo-ściernej. Dzięki swoim licznym zaletom, obróbka którą opisywane obrabiarki realizują, jest coraz częściej stosowana, obserwuje się więc próby jej zautomatyzowania – także przedstawione w opracowaniu.

EN

In the first part of the study (OM 4/19) the principles of operation of pneumatic cabin blast machines were presented, while this part presents examples of constructional solutions of these machines that enable blasting. The machining that the described machine tools are performing thanks to their numerous advantages is being used more and more often, so attempts to automate it are observed – also presented in the study.

15

Simulation of FLY-ROCK DISTANCe as a Function of Blast Conditions: a Case Study in Vietnam

Nguyen Anh Tuan, Pham Van Hoa, Pham Van Viet, Tran Dinh Bao, Le Thi Hai

Inżynieria Mineralna

|

2020

|

no. 2, vol. 1

275--282

EN

The prediction of fly-rock distances is a big problem in the blasting areas of open-pit mines. The fly-rock distance plays a crucial role in the reduction and control of blasting accidents in quarries. This paper proposes the modelling of the contact dynamics as a non-smooth discrete element method (NSCD). Then, the fly-rock phenomenon is simulated using this NSCD method. This approach was to develop a model that correlates to blast conditions, initial fly-rock/rock-fall velocities and permits the computation of fly-rock range from randomization orbits. The results showed that the NSCD method is a good means for the simulation with the variability of blasting parameters. This method is to relate the initial fly-rock velocity to blast conditions and then uses ballistic trajectories to compute the maximum fly-rock distance. Finally, it should be noted that the proposed simulation of fly-rock trajectories which shows the distribution of fly-rock bounce heights above the ground level with the different coefficient of restitution range as a function of blast conditions. It should be used in the Ninh Dan limestone quarry belonging to the Song Thao Cement, Phu Tho province (Vietnam), and it should be directly used in the same other quarries.

PL

Przewidywanie odległości między odrzucającymi skałami ma duży problem w kopalniach odkrywkowych. Odległość między skałami odrzucającymi odgrywa niezwykłą rolę w ograniczaniu i kontrolowaniu wypadków spowodowanych robotami strzelniczymi w kamieniołomach. W artykule, zaproponowano modelowanie dynamiki kontaktu jako metodę elementów dyskretnych Non-Smooth (NSCD). Następnie symuluje się zjawisko fly-rock metodą NSCD. Zastosowane podejście polegało na opracowaniu modelu, który kore-luje warunki wybuchów, początkowe prędkości lotnych skał i pozwala na obliczenie zasięgu fali z orbity losowej. Wyniki pokazały, że NSCD jest dobrym środkiem do symulacji przy zmienności parametrów strzałów. Ta metoda zastosowana w niniejszych badaniach polega na powiązaniu początkowej prędkości latających skał z warunkami wybuchu, a następnie wykorzystaniu trajektorii balistycznych do obliczenia maksymalnej odległości między latającymi skałami. Na koniec należy zauważyć, że zaproponowano symulację trajektorii odrzucających skał, która pokazuje rozkłady wysokości odbijania skał nad poziomem ziemi przy różnym współczynniku zakresu restytucji w funkcji warunków techniki strzelniczej. Powinien być stosowany w kamieniołomie wapienia Ninh Dan należącym do cementu Song Thao w prowincji Phu Tho (Wietnam) i powinien być stosowany w podobnych kamieniołomach.

16

New drilling design by doubled holes in surface mines

Remli Samir, Benselhoub Aissa, Khebbab Rachid, Fellouh Nacereddine

Inżynieria Mineralna

|

2020

|

no. 2, vol. 2

189--192

EN

Drilling of holes in mines is a very important factor that generally has a great influence on the operability, productivity and especially the cost of a ton of ore extracted. therefore, in this paper, we will see a technique that helps us to optimize the drilling-blasting ring by making doubled holes in each position in the block to be fragmented at the company of CGMSG (quarry of aggregates).

PL

Wiercenie otworów w kopalniach jest bardzo ważnym czynnikiem, który generalnie ma duży wpływ na funkcjonalność, produktywność, a zwłaszcza na koszt tony wydobytej rudy. Dlatego w tym artykule przedstawiono technikę, która pomaga zoptymalizować prace wiertniczo- strzałowe poprzez wykonanie podwójnych otworów w każdym miejscu w bloku do rozdrobnienia. Badania przeprowadzono w firmie CGMSG (kamieniołom kruszyw).

17

Role of ergonomics in the selection of stemming plugs for surface mining operations

Rehman Atta Ur, Emad Muhammad Zaka, Khan Muhammad Usman

Archives of Mining Sciences

|

2020

|

Vol. 65, no. 1

59--70

EN

Stemming plugs are one of the widely used accessory in surface mining operations. Stemming plugs assist conventional stemming material in gas retention and help in better fragmentation and explosive utilization. Effective use of the stemming plugs results in economic benefits and enhance the efficacy of the project. Economic and productive viability of stemming plugs have been conducted in depth by different researchers. Addition of stemming plugs to a new system requires ergonomic challenges for operators conducting drilling and blasting operation. Induction of a newer product in already established system is subject to overall positive feedback. This work investigates ergonomics of three different stemming plugs introduced to a limestone quarry in Pakistan. The stemming plugs were evaluated based on extra time needed, workers feedback, failures during operation, recovery time after failure and number of extra equipment required to carry out the operation. Points based matrix was established with likeliness of each plug and based on overall scores stemming plug 1 was most acceptable followed by stemming plug 3. Stemming plug 2 was disliked by operation and did not reach the level of acceptability of operators. This work will help stemming plug making industry in adapting to best practices by incorporating ergonomics of plugs in designing. Literature shows no previous work on ergonomics of stemming plugs.

18

Prediction of blast-induced ground vibration using gene expression programming (GEP), artificial neural networks (ANNS), and linear multivariate regression (LMR)

Shakeri Jamshid, Shokri Behshad Jodeiri, Dehghani Hesam

Archives of Mining Sciences

|

2020

|

Vol. 65, no. 2

317--335

EN

In this paper, an attempt was made to find out two empirical relationships incorporating linear mul-tivariate regression (LMR) and gene expression programming (GEP) for predicting the blast-induced ground vibration (BIGV) at the Sarcheshmeh copper mine in south of Iran. For this purpose, five types of effective parameters in the blasting operation including the distance from the blasting block, the burden, the spacing, the specific charge, and the charge per delay were considered as the input data while the output parameter was the BIGV. The correlation coefficient and root mean squared error for the LMR were 0.70 and 3.18 respectively, while the values for the GEP were 0.91 and 2.67 respectively. Also, for evaluating the validation of these two methods, a feed-forward artificial neural network (ANN) with a 5-20-1 structure has been used for predicting the BIGV. Comparisons of these parameters revealed that both methods successfully suggested two empirical relationships for predicting the BIGV in the case study. However, the GEP was found to be more reliable and more reasonable.

19

Współczesne pneumatyczne kabinowe oczyszczarki strumieniowo-ścierne Część I

Woźniak Kazimierz

Obróbka Metalu

|

2019

|

nr 4

39--44

EN

Abrasive blasting is one of the most common methods of loose abrasive blasting. It consists in the fact that abrasive grains are lifted up at high speed by a fluid (liquid, gas or a mixture of both) under increased pressure or by the centrifugal force of a shot wheel. The resulting abrasive stream is directed to the workpiece surface in order to perform the machining work and clean the surface.

PL

Obróbka strumieniowo-ścierna należy do najbardziej rozpowszechnionych metod obróbki ściernej luźnym ścierniwem. Polega ona na tym, że ziarna ścierne unoszone są z dużą prędkością przy użyciu płynu (cieczy, gazu lub cieczy i gazu) występującego pod zwiększonym ciśnieniem lub przy użyciu siły odśrodkowej koła rzutowego. Powstający wówczas strumień ścierny kierowany jest na powierzchnię obrabianą dla wykonania pracy skrawania i oczyszczenia tej powierzchni.

20

Field investigation in the detonation behavior of emulsion explosive column induced with air gaps

Balakrishnan Vineeth, Pradhan Manoj, Dhekne P. Y.

Mining Science

|

2019

|

Vol. 26

55--68

EN

In blasting of soft to medium hard rock, the problem of high density resulting in excessive utilization of emulsion explosive is well known. The authors have conducted some experimental blasts to delve into the detonation behavior of conventional blasting and various other explosive consumption reduction techniques which induce air gaps using plastic tubes, plastic bottles or plastic balls in the explosive column. Resistance wire technique is used for gauging in-hole continuous velocity of detonation. The VOD varies from 5321.6 m/s to 4544.2 m/s and from 5123.4 m/s to 4274.2 m/s in conventional site mixed emulsion column and distributed spherical air gap column respectively. The detonation behavior is stable and similar in both these cases. While using plastic bottles or plastic tubes as air gaps, the VOD is fluctuating from 4636.3 m/s to 3268.4 m/s and from 4935.9 m/s to 3362.8 m/s respectively with a collapse of about 12 % from the average VOD of conventional SME column. The VOD falls abruptly when the detonation wave encounters large air gaps but it is successfully travelling through the air gaps making the detonation behavior more capricious.