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1

Exploring the Relation between Seismic Coefficient and Rock Properties Through Field Measurements and Empirical Model for Evaluating the Effect of Blast-Induced Ground Vibration in OpenPit Mines: A Case Study at the Thuong Tan III Quarry (Vietnam)

Tran Quang Hieu

Inżynieria Mineralna

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2021

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no. 2

567--577

EN

Blasting is one of the most effective methods for fragmenting rock in quarries. Nevertheless, its adverse effects are significant, especially blast-induced ground vibration. Field measurement and empirical equations are simple methods to determine and estimate the intensity of blast-induced ground vibration. However, we cannot evaluate the effects of blast-induced ground vibration on the surrounding environment based on these outcomes. Therefore, this study explores the relation between seismic coefficient and rock properties through field measurements and an empirical model for evaluating the effect of blast-induced ground vibration in open-pit mines. Accordingly, the seismic coefficient (K) is considered the main objective in this study. Firstly, it was determined based on the rock properties. Subsequently, an empirical model for estimating blast-induced ground vibration was developed based on field measurements. This empirical equation was then expanded to determine K to check whether it matches the determined K by the rock properties. Finally, it was used as the threshold to determine the maximum explosive charged per delay to ensure the safety of the surrounding environment from blastinduced ground vibration. For this aim, the Thuong Tan III quarry (in Binh Duong province, Vietnam) was selected as a case study. Fifth-teen blasting events with a total of 75 blast-induced ground vibration values were recorded and collected. An empirical equation for estimating blast-induced ground vibration was then developed based on the collected dataset, and K was determined in the range of 539 to 713 for the Thuong Tan III quarry. Based on the measured blast-induced ground vibrations, developed empirical model, and K values, the Phase 2 software was applied to simulate the effects of blast-induced ground vibration on the stability of slopes as one of the impacts on the surrounding environment. From the simulation results, we can determine the maximum explosive charged per delay for each type of rock to ensure the stability of the slope.

2

The Influence of Voltage Quality on Asynchronous Motor Performance of EKG Excavator in Open Pit Mines – Vinacomin

Ngo Xuan Cuong, Do Nhu Y., Tran Quang Hieu

Inżynieria Mineralna

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2020

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no. 2, vol. 1

139--145

EN

At present, in open-pit mining, the main and most important electrical load is the electric excavator, and currently using a variety of EKG excavators. 6kV electrical network in open pit mining has the characteristics such as long outgoing lines, use high-powered equipment, multiple branches, and increasing use of power electronics on the grid, this reduces the quality of the power supplied to the excavators EKG, resulting in an increase in power losses thereby greatly affecting the performance of the excavators. Previous studies on the quality of the power supplied to the excavator often only mentioned voltage deviations, in addition to this factor, the performance of the excavator is also greatly affected by nonsinusoidal voltage waveforms of the excavator power supply. This paper analyzes the influence of the nonsinusoidal of voltage on the power loss of electric motors used in EKG electric excavators in open pit mining based on the method of electromagnetic analysis and verification on simulation software.

PL

Obecnie, EKG są powszechne koparki stosowane w kopalnictwie odkrywkowym Wietnamu. Sieć elektryczna 6kV w kopalniach odkrywkowych ma takie cechy, jak długie linie wychodzące, zastosowanie sprzętu o dużej mocy, wiele odgałęzień co obniża jakość energii dostarczanej do koparek EKG, skutkując wzrost strat mocy, co znacząco wpływa na wydajność koparek. Dotychczasowe badania jakości energii dostarczanej do koparki często wskazywały tylko na odchylenia napięcia. W artykule, przeanalizowano wpływ napięcia niesinusoidalnego na straty mocy silników elektrycznych stosowanych w koparkach elektrycznych EKG w górnictwie odkrywkowym w oparciu o metodę analizy elektromagnetycznej i weryfikacji w oprogramowaniu symulacyjnym.

3

Design of Pre Blasting (Pre-Splitting) in Tan Cang Quarry NO.1 in Vietnam

Nguyen Dinh An, Pham Thai Hop, Le Cong Dien, Tran Quang Hieu, Tran Dinh Bao

Inżynieria Mineralna

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2020

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no. 2, vol. 1

155--162

EN

Nowadays, construction material quarries in Dong Nai Province are exploiting with large quarrying depth, and the annual output could reach to tens of million cubic meters. The blasting frequency could be reached to hundreds of times, so the frequency is the major reason decreasing the cohesion of rock mass. Therefore, the surrounding area of blasting holes is broken, especially the area next to the final border where bench slope angle is not implemented as that of design stage, as well as the back break, also causes fractures on the bench slope, resulting in instability and unsafety due to falling rock. In this paper, the author also wants to introduce the pre blasting and the method to define blasting parameters to increase the stabilization of Slopes in Tan Cang quarry NO.1 in Vietnam.

PL

Obecnie kamieniołom litych surowców skalnych w prowincji Dong Nai prowadzi eksploatację na dużej głębokości. Roczne wydobycie materiałów budowlanych dochodzi do kilkudziesięciu milionów metrów sześciennych. Duża ilość wybuchów powtarzających się rocznie jest główną przyczyną osłabienia więzi skalnej w masie wraz z rozprzestrzenianiem się fal sejsmicznych z wybuchów powodują więc drgania i niszczenie warstwy, osuwisko kopalniane i różne deformacje nieciągłe. W artykule, przedstawiono metody wyznaczenia granicznych parametrów robót strzałowych oraz diagram wybuchów w celu zwiększenia stabilności zbocza w kamieniołomie nr 1 -Tan Cang 1 w Wietnamie.

4

Developing an Advanced Soft Computational Model for Estimating Blast-Induced Ground Vibration in Nui Beo Open-pit Coal Mine (Vietnam) Using Artificial Neural Network

Nguyen Hoang, Bui Xuan‑Nam, Tran Quang Hieu, Nguyen Quoc Long, Vu Dinh Hieu, Pham Van Hoa, Le Qui Thao, Nguyen Phu Vu

Inżynieria Mineralna

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2019

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R. 21, nr 2/2

58--73

EN

The principal object of this study is blast-induced ground vibration (PPV), which is one of the dangerous side effects of blasting operations in an open-pit mine. In this study, nine artificial neural networks (ANN) models were developed to predict blast-induced PPV in Nui Beo open-pit coal mine, Vietnam. Multiple linear regression and the United States Bureau of Mines (USBM) empirical techniques are also conducted to compare with nine developed ANN models. 136 blasting operations were recorded in many years used for this study with 85% of the whole datasets (116 blasting events) was used for training and the rest 15% of the datasets (20 blasting events) for testing. Root Mean Square Error (RMSE), Determination Coefficient (R2), and Mean Absolute Error (MAE) are used to compare and evaluate the performance of the models. The results revealed that ANN technique is more superior to other techniques for estimating blast-induced PPV. Of the nine developed ANN models, the ANN 7-10-8-5-1 model with three hidden layers (ten neurons in the first hidden layer, eight neurons in the second layers, and five neurons in the third hidden layer) provides the most outstanding performance with an RMSE of 1.061, R2 of 0.980, and MAE of 0.717 on testing datasets. Based on the obtained results, ANN technique should be applied in preliminary engineering for estimating blast-induced PPV in open-pit mine.

5

A Lasso and Elastic-Net Regularized Generalized Linear Model for Predicting Blast-Induced Air Over-pressure in Open-Pit Mines

Bui Xuan‑Nam, Nguyen Hoang, Tran Quang Hieu, Bui Hoang‑Bac, Nguyen Quoc Long, Nguyen Dinh An, Le Thi Thu Hoa, Pham Van Viet

Inżynieria Mineralna

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2019

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R. 21, nr 2/2

8--20

EN

Air overpressure (AOp) is one of the products of blasting operations in open-pit mines which have a great impact on the environment and public health. It can be dangerous for the lungs, brain, hearing and the other human senses. In addition, the impact on the surrounding environment such as the vibration of buildings, break the glass door systems are also dangerous agents caused by AOp. Therefore, it should be properly controlled and forecasted to minimize the impacts on the environment and public health. In this paper, a Lasso and Elastic-Net Regularized Generalized Linear Model (GLMNET) was developed for predicting blast-induced AOp. The United States Bureau of Mines (USBM) empirical technique was also applied to estimate blast-induced AOp and compare with the developed GLMNET model. Nui Beo open-pit coal mine, Vietnam was selected as a case study. The performance indices are used to evaluate the performance of the models, including Root Mean Square Error (RMSE), Determination Coefficient (R2), and Mean Absolute Error (MAE). For this aim, 108 blasting events were investigated with the Maximum of explosive charge capacity, monitoring distance, powder factor, burden, and the length of stemming were considered as input variables for predicting AOp. As a result, a robust GLMNET model was found for predicting blast-induced AOp with an RMSE of 1.663, R2 of 0.975, and MAE of 1.413 on testing datasets. Whereas, the USBM empirical method only reached an RMSE of 2.982, R2 of 0.838, and MAE of 2.162 on testing datasets.