Technological and Economic Analysis of the Application of Surface Miner on the Example of a Limestone Deposit in Poland

Mining a deposit utilizing surface miner is very popular in many countries. Presently, a surfaceminer has also experimented with extracting different deposits: bauxite, hematite, sandstone, shale etc.Surface miners can completely eliminate drilling and blasting operation and primary crushing unit, thusreducing their associated environmental hazards. Apart from this, the sized excavated material increasestransport or conveying efficiency and saves the energy requirement in processing. So far, these machineshave not been used in Poland. To evaluate this technology, tests were carried out on one of the limestonedeposit in Poland. During these tests, basic parameters of efficiency, output quantity and mining costswere defined. The conducted tests have shown that this technology cannot be used in all geological andmining conditions. Therefore, the article presents the advantages and disadvantages of using surfaceminer, taking into account the Polish geological and mining conditions.

Optimization study of blasting operations in Roşia Poieni open pit mine, Romania

Purpose. Drilling-blasting technology is one of the simplest and most often used techniques in open pit mining. This allows the excavation of a large volume of rock and useful mineral substance. The operation of blasting using the energy of explosives plays an important role in open pit exploitation, being also the key element of the blasting process through which a corresponding granulometry is obtained. This operation is a part of a series of interdependent operations, in the sense that each operation determines a certain result that will be an important element for the next operation that takes place in the working face. Consequently, the blasting operation with explosives should not be considered as an independent act. A global approach to the entire production technological process including blasting is required. Methods. In the optimization study, the basic method consisted in the analysis of the blasting operations performed at the drilling diameter of 250 mm (blasting technology used in Roşia Poieni open pit mining) and simulation of the excavation of the same rock volume, with the optimization of the explosive charge distribution at two other drilling diameters: 200 and 150 mm. Findings. The main problems when shooting 250 mm dia holes are caused by the length of the tamping in the mineralized rock that leads to the appearance of blocks with dimensions which are maximum allowed in the crusher tank (1.2-1.3 m). That is why discontinuous loads with intermediate tamping are used – the method that successfully limits their number. In order to obtain a granulometry corresponding to the primary crushing operation, which will allow to decrease the crushing costs, it is necessary to use smaller drilling diameters, but with productivity high enough to ensure the optimal development of the extraction process. Originality. Based on the performed study, it is recommended to use the discontinuous load, preserving the total length of the explosive charge. In the zones where the rocks have a Protodiakonov coefficient f > 6.5, it is recommended to apply an appropriate drilling diameter (150-200 mm) and use the intermediate tamping at 2-3 m length to limit the upper stemming area to a maximum of 7 m (to limit or eliminate the occurrence of oversized blocks). Practical implications. The research results will enhance the geometric and safety factors of the operation, limiting the explosion effect on the massif and the environment and reducing the total costs of the cutting operation. The cost of explosives and initiating materials can be reduced by using a smaller quantity of explosive gels in a dry environment (12-18 kg/hole), the difference in the explosive charge length being completed with AM 1.

Application of Artificial Neural Network (ANN) for Prediction and Optimization of Blast-Induced Impacts

Drilling and blasting remain the preferred technique used for rock mass breaking in mining and construction projects compared to other methods from an economic and productivity point of view. However, rock mass breaking utilizes only a maximum of 30% of the blast explosive energy, and around 70% is lost as waste, thus creating negative impacts on the safety and surrounding environment. Blast-induced impact prediction has become very demonstrated in recent research as a recommended solution to optimize blasting operation, increase efficiency, and mitigate safety and environmental concerns. Artificial neural networks (ANN) were recently introduced as a computing approach to design the computational model of blast-induced fragmentation and other impacts with proven superior capability. This paper highlights and discusses the research articles conducted and published in this field among the literature. The prediction models of rock fragmentation and some blast-induced effects, including flyrock, ground vibration, and back-break, were detailed investigated in this review. The literature showed that applying the artificial neural network for blast events prediction is a practical way to achieve optimized blasting operation with reduced undesirable effects. At the same time, the examined papers indicate a lack of articles focused on blast-induced fragmentation prediction using the ANN technique despite its significant importance in the overall economy of whole mining operations. As well, the investigation revealed some lack of research that predicted more than one blast-induced impact.

Optimized Support Vector Machines Combined with Evolutionary Random Forest for Prediction of Back-Break Caused by Blasting Operation

Back-break is an adverse event in blasting works that causes the instability of mine walls, equipment collapsing, and reduction in effectiveness of drilling. Therefore, it boosts the total cost of mining operations. This investigation intends to develop optimized support vector machine models to forecast back-break caused by blasting. The Support Vector Machine (SVM) model was optimized using two advanced metaheuristic algorithms, including whale optimization algorithm (WOA) and moth–flame optimization (MFO). Before the models’ development, an evolutionary random forest (ERF) technique was used for input selection. This model selected five inputs out of 10 candidate inputs to be used to predict the back break. These two optimized SVM models were evaluated using various performance criteria. The performance of these two models was also compared with other hybridized SVM models. In addition, a sensitivity evaluation was made to find how the selected inputs influence the back-break magnitude. The outcomes of this study demonstrated that both the SVM–MFO and SVM–WOA improved the performance of the standard SVM. Additionally, the SVM–MFO showed a better performance than the SVM–WOA and other hybridized SVM models. The outcomes of this research recommend that the SVM–MFO can be considered as a powerful model to forecast the back-break induced by blasting.

Low density optimization of emulsion explosive to improve blasting quality (MNK Max70)

PT Multi Nitrotama Kimia is a mining service company engaged in providing blasting services and the largest sales of explosives in Indonesia. PT Pamapersada Nusantara jobsite Kideco Jaya Agung is one of the customers of PT Multi Nitrotama Kimia in the blasting service business unit. On a far more optimal side, the development of commodity price conditions and operational needs is a common concern. From these conditions, one of the best target cost controls for blasting and fragmentation is to make adjustments and improvement to the quality and quantity of the use of bulk products. The high use of bulk products at the Kideco Jaya Agung Jobsite is a particular concern, especially for rocks that require a high powder factor value, thereby increasing blasting operation costs. From this condition, PT Multi Nitrotama Kimia strives to optimize the bottom value of density product emulsion MNK Max70 using chemical improvement from the previous 1.15 gr/cc to 1.05 gr/cc. This improvement has brought good results, where optimization in terms of using bulks product and blasting quality such as fragmentation and Velocity of Detonation (VOD) values are still in accordance with product standards.

Technology of Coal Seam Long Borehole Blasting and Comprehensive Evaluation Method of Pressure Relief Effect in High Rockburst Proneness Longwall Panel

On August 2, 2019, a catastrophic rockburst disaster occurred in Tangshan mine, causing death of 7 miners. After the investigation, the coal mine is facing reproduction. Taking the 0291 panel as the engineering background, this paper studies the coal seam blasting pressure relief and ground stress monitoring technology in working face retreat. During the roadway development and working face excavation, coal seam blasting was adopted to transfer the high ground stress of coal seam to the deep ground of the coal body. The blasting operation is presented in detail in this paper. In the working face retreat stage, drilling powder method, hydraulic shield resistance monitoring, roof displacement, and vibration monitoring methods are implemented. The results show that the pressure relief range of coal seam is 4–12 m in the coal mass after blasting. The shield working resistance is stable at 20–30 MPa. The range of relative displacement of the roof is about −1.0 to 2.5 mm, and the maximum vertical vibration velocity is in the range of 7–11 cm/s, up to 12 cm/s. The measured parameters are acceptable, so it is concluded that 0291 panel can be safely mined. This study provides a reference for the coal seam blasting design for rockburst coal mine and provides a technical means for the analysis of pressure release effect and dynamic pressure monitoring during working face retreating.

Combatting lime kiln ringing problems at the Arauco Constitución mill

The lime kiln at the Arauco Constitución mill experienced severe ringing problems requiring it to be shut down for ring removal every 3 to 6 months. The mill controlled the problems by blasting ring deposits off during operation with its existing industrial shotgun and a newly installed Cardox liquid carbon dioxide (CO2) cartridge system. Various ring blasting procedures were tested to determine the optimum ring location and thickness to blast; the optimum depth to insert the CO2 cartridge into the kiln; and the most effective blasting frequency and sequence to employ. The best strategy was found to be the weekly blasting operation that alternated between the liquid CO2 cartridge and the industrial shotgun, with the CO2 cartridge inserted into the ring mass, 20 cm (8 in.) away from the refractory brick surface, and the shotgun aimed at rings at about 28 m (92 ft) from the kiln discharge end. With each blasting event removing considerably more rings than before, it takes a longer time for rings to rebuild, allowing the kiln to run continuously between annual maintenance shutdowns with only a few short (< 4 h) downtimes for ring removal. This substantially reduces the costs associated with ring removal and lime replacement during unscheduled shutdowns.

Application of Split Desktop Image Analysis and Kuz-Ram Empirical Model for Evaluation of Blast Fragmentation Efficiency in a Typical Granite Quarry

Evaluation of fragmentation efficiency is an integral aspect of blasting operation. This study therefore assesses the efficiency of fragmentation size at Eminent granite quarry, Ibadan, Nigeria using Split Desktop software and Kuz-Ram empirical model. Five muckpiles of blasted rocks with the same blast design were analysed. The muckpile images were captured using smart high precision digital camera and uploaded into computer for Split Desktop analysis. The results of the fragment size distribution obtained from Kuz-Ram vary slightly with that of the Split Desktop but follow similar trend. The average values of F80 and F90 from the Split Desktop image analysis were 90.96 cm and 98.24 cm respectively. The Kuz-Ram model values for F80 and F90 were 88.52 cm and 92.95 cm respectively. The results of the Split Desktop were compared to the results obtained from the Kuz-Ram experiential model. The findings showed that the results obtained from Kuz-Ram empirical model were in conformity with the results from the Split Desktop software based on empirical relationship. Hence, the model is good for preliminary evaluation of blast design. Keywords: Blasting, Particle Size Distribution, Split Desktop Software, Muckpile, Fragmentation Indicator

Evaluation of the safety parameters for a permitted explosive type emulsion

When preparing a permitted explosive recipe an energy or an explosive heat is considered, which should ensure the detonability of the system and at the same time a power that satisfies the purpose for which it will be used, under the conditions of firedamp hazardous mines. The safety parameters for the explosive charges used in the firedamp hazardous mines are decisive, in order to ensure the safety and health requirements at work together with the efficient performance of the blasting operation. The permitted explosive type emulsion is recommended to be used in underground mines, open pit mines as a special methane explosive and can be used where a coal dust and/or methane explosion hazard exists can be loaded into dry and wet blasting holes and it can be used for mechanical loading. The permitted explosive type emulsion is a Detonator-sensitive explosives that can be reliably initiated in an unconfined state by a No. 8 strength detonator it have safety handling characteristics because of the relatively low sensitivity to friction, shock and impact. Technological changes due to the change of suppliers of certified explosives for civil use for underground use in the firedamp hazardous mines, involve reassessing the safety and efficiency of the loads made with these products, which have not been tested and evaluated for the conditions from the Jiu Valley mines.