Papers by Keyword: Quarry

Abstract: Comparison of experimental and calculated data of the excavator utilization factor in time (K_u) according to the current methods showed the absence of even a correlation between them r = 0.17, which indicates the inexpediency of using the basic models that are the basis of these methods. The reason for the low correspondence is that the excavation processes are complex random dynamic non-stationary processes, and the models that are the basis of almost all current methods are simple deterministic static models that cannot successfully operate at the level required for such processes. In the work with the application of the theory of mass service systems, a set of probabilistic dynamic non-stationary models in the form of Markov-Kolmogorov equations was developed to describe the probability of states, both for each of the selected subsystems of downtime of excavation works, and for the “excavator face” system as a whole. Comparison of the actual values of the coefficient (K_u) obtained as a result of the experiment allows us to recommend the developed set of models as the basis of the methodology for calculating K_u (r = 0.70).

Abstract: In the challenging environment of the Negeri Roadstone Malaysia quarry, maintaining accuracy in the weight measurement of raw materials and finished products is paramount. This paper presents an in-depth analysis of an integrated weighing system comprising load cells and ultrasonic sensors, used strategically at the quarry site. By leveraging the precision of strain gauge technology inherent in load cells and the distance-measuring capabilities of ultrasonic sensors, the system aims to offer accurate weight estimations across varying distributions of materials, mainly sand. The load cell yields an average weight of 703.8192g, 701.8220g and 702.4949g which is very close to the actual weight of the sand (700g). Experimental results highlight the sensitivity of ultrasonic measurements to the distribution pattern of sand, emphasising the importance of material consistency for accurate volume-to-weight conversions. Furthermore, integrating the Node-RED platform showcases real-time data visualisation, enhancing the system's usability and data analysis capabilities. Through this study, we underscore the potential and challenges of employing a hybrid weighing system, offering insights for future implementations in similar industrial settings.

Abstract: Blasting has been adjudged as the cheapest method of hard rock fragmentation. The itinerary of rock breakage through blasting in open pit mines is a complex portent which is measured via various variables and parameters. This research investigates the impact of short burden and spacing on blasting output with the aim of establishing a more suitable and economically viable approach. Trials and proposed methods were adopted to investigate blasting geometry results. Results obtained showed that the trials method of 1.2 m by 1.2 m and proposed blasts method of 2.0 m by 2.0 m burden and spacing at 9m depth, covered areas were 80.64 m² and 99.36 m² respectively, while at 12 m depth with same blasting geometry covered 224 m² and 276 m² respectively. The first trial and proposed blasts methods using burden and spacing of 1.2 m by 1.2 m produced 2,583.71 tons and 2,387.62 tons respectively. Hence, with the use of 2.0 m by 2.0 m burden and spacing, the blasts operations produced 7,176.96 tons and 6,632.28 tons respectively. Meanwhile, the results revealed that, short burden (≤ 1.2 m by 1.2 m) threatens safety in which flyrocks are spawned and it’s dangerous to equipment and personnel, at the same time, the areas covered, quantity produced (i.e. volume) and the tonnage were small compared to the engineering control methods. However, it was found that the trials blast methods were not economically worthwhile in terms of explosive consumption compared to the proposed measure of the geometry.

Abstract: Sardinia (Italy) produces a vast array of natural stones for ornamental use. Besides the internationally known pink and gray granites and the famous limestone known as Orosei marble, a wide range of vulcanites (basalts and “trachytes”) and phyllites - including yellow and ghiandone granites - are also produced. Orosei marbles are some of the most requested types today, which are marketed especially to China. However, there are a number of Sardinian natural stones, which have been quarried and marketed for fifty years, although no image or footage has been published yet: a mention of this natural stones has been only made in some old list of Sardinian stones. For this reason, authors suggested the publication of a poster (70 cm x 100 cm) showing a collection of natural stones quarried for ornamental purposes in Sardinia over the last fifty years. The poster includes a user-friendly map that has been adapted for school use and as a public resource in libraries. There are no previous publications showing a similar wide range of Sardinian stones. The poster offers scientific information about lithology, quarrying sites, dimension stone producing areas, quarries of historical and/or archaeological interest, historical trend in quarries output, technical properties, stone surface workability and a glossary.

Abstract: The relationship between grindability of blast-hole cuttings, strength parameters and bit wear rate were investigated. In order to achieve this, drill cuttings were collected from twenty blast-holes drilled in a quarry. The samples were tested in the laboratory for Silica content using X-Ray Fluorescence (XRF) spectrometer. Also, the length of button worn on the surface of bit was measured at regular interval with aid of digital vernier caliper on the field as drilling operation progresses to determine wear rate. Sieve analysis was used to determine the size distribution of the blast hole cuttings in the laboratory using sieve shaker while grindability was determined using the ball mill, by grinding for certain number of revolutions. The result obtained show that the weight of drill cuttings retained on 850μm decreases while weight retained on 75μm increases as wear rate increases. Grindability was correlated with wear rate and weight retained at 75μm sieve, the value of multiple coefficients of correlation is 0.126 and 0.064 respectively, this show that there is no relationship between grindability, wear rate and weight of cuttings retained on 75μm. The result of correlation of wear rate and weight retained at 75μm shows that strong relationship exist between them and the value of multiple coefficient of correlation is 0.892.

Abstract: The application of photogrammetry, with a particular emphasis on 3D modelling and monitoring, is of interest in the field of underground mining transportation. In the article, a practical assignment concerning the creation of a 3D model with the aid of an ordinary photographic camera and a personal computer, practically conducted by a student with the aid or supervision of a lecturer at the University of Ljubljana, Slovenia, as a part of the academic process that is, in the effort to instil practical knowledge into students, part of pursuing a mining degree, is described in detail, delineating all the procedures involved, any appearing problems, the means to deal with any appearing problems and the means to employ the obtained 3D model in the future. The aim of creating the 3D model was to demonstrate the convenience of applying photogrammetry in the fields of mining, geology and geotechnology, as well as to introduce a tool that is, in terms of its efficiency, relatively poorly represented in Slovenia and, taking into account its affordability along with its efficiency, to consider its practical application in the mining, geological and geotechnological professions.

Abstract: This paper focuses on computational fluid dynamics (CFD) simulation of the dynamic exploited influence of wind field in the open pit quarry. We have picked up 3 normal exploitation parameters, e.g. the exploited depth z, the type of small hills and the measured velocity u₁, 7 simulated experiments have been done by software Fluent as well. In our experiments, the features of velocity field around the mine are shown, with the effects of open pit quarry, so as to analyze the changes of wind speed when it gets through this mine. To be exact, it will be possible to deduce there is negative correlation between the velocity decreased gratitude and the exploited depth. Besides, with the shelter effect of a small hill, the wind speed tends to slow down near this hill, and turn back to rise until the flow leaves the hill far away. The velocity decreasing has positive correlation with the measured velocity u₁, and the reverse flow is more likely to appear with higher u₁.

Abstract: Estimation of the respective productivities of men and women stone crushers in Artisanal and Small Scale Granite Quarries was carried out by collecting data from sample sites and conducting statistical treatment of collected data. An analysis of the results shows that the productivities of men and women stone crushers are 1.1 and 0.6 tonnes per day. Based on these results, a rating scale of output and required manpower in Artisanal Granite quarries was developed using interval and nominal rating methods.

Abstract: Rock slope failure mechanisms were assessed in this study using KOPEC and RCC quarries as case studies in Oyo state. Discontinuities such as joints and bedding planes were obtained through face mapping and scanline survey of the excavated slopes of the quarries. Stereographic projections of the discontinuities were generated using ROCKPACK III and the stereonets analyzed in accordance with Markland’s plane failure analysis. The results of the analyses show that there are possibilities of plane failures in the south- east region of KOPEC quarry slope face and south –west region of RCC quarry slope face. It is therefore recommended that constant monitoring of the slope failure should be done and the slope angle should be less than 700 and 600 for KOPEC quarry and RCC quarry respectively.