SPT-CPT correlation in Southeast Queensland, Australia

Among the most popular in situ investigation techniques for identifying subsurface strata, cone penetrometer testing (CPT) and standard penetrometer testing (SPT) are employed in geotechnical engineering. In fact, both tests are adopted to correlate a wide range of geotechnical parameters in various design applications. The cost associated with conducting both in situ tests at the same locations often results in one method being chosen over the other. Hence, engineers have to corelate one of the tests’ parameters into the other test using empirical correlation in translating SPT blow counts (SPT-N) into CPT cone tip resistance (CPT-qc). However, disadvantages of this in situ test are that it does not directly quantify geotechnical parameters but uses correlations which are significantly influenced by soil properties. Also, many of correlations do not provide sufficient background on the statistical approach. This study investigates the conformity of the empirical correlations against local SPT-CPT correlation for different soil occurrences in Southeast Queensland (SEQ), adopting a linear regression model to validate the degree of the relationship. Seven soil groups were classified in SEQ, comprising cohesionless and cohesive soil. The results of the SEQ samples showed a strong liner relationship (r = 0.69 – 0.89) with at least 50% of data points coinciding with the regression line (R2 = 0.48 – 0.80). It follows that for some soil groups, the published correlation agrees well with the SEQ study, while others did not

Investigating the effect of coal macerals on the recovery rate of the flotation process- a case study

Alborz-Sharghi coal washing plant is one of the most significant coal producers in Iran, which has a low recovery rate in the flotation process. This paper investigates the effect of coal macerals types on the flotation recovery rate. For this purpose, a comprehensive sampling procedure was conducted on the feed of the flotation system. Afterwards, the required polished sections of the samples were prepared for detecting the macerals. After conducting a series of flotation tests on the samples, the recovery rate results were compared based on detected macerals on the polished sections. The results revealed that the flotation recovery rate increased with the rising vitrinite contents. However, it decreased with increasing fusinite and liptinite contents

Predicting the pyrite oxidation process within coal waste piles using multiple linear regression (MLR) and teaching-learning-based optimization (TLBO) algorithm

Coal mining often leads to significant environmental hazards and health concerns when sulfide minerals, particularly pyrite, are associated with coal waste. The oxidation of pyrite typically generates acid mine drainage, a significant problem. This paper presents two mathematical relationships using a teaching-learning-based optimization (TLBO) algorithm for predicting pyrite oxidation and pH changes within a coal waste pile from Alborz-Markazi in northern Iran. A dataset was built based on historical data to achieve this goal. Some influential parameters comprising the depths of the various samples, oxygen fraction, and bicarbonate concentrations were considered as input data, while the outputs were pyrite content and pH. Then, the best statistical relationships were suggested between input and output parameters employing curve and surface fitting methods. Afterward, two multiple linear regression (MLR) models were presented for predicting pyrite content and pH. Also, two relationships have been suggested for predicting the same outputs by applying the TLBO algorithm. Comparison of the results of the latter method with the results obtained using the statistical technique, including correlation coefficient and root mean squared error (RMSE), revealed that the TLBO could predict the outcomes better than the MLR

Application of Computational Fluid Dynamics (CFD) for Simulation of Acid Mine Drainage Generation and Subsequent Pollutants Transportation through Groundwater Flow Systems and Rivers

Many environmental problems associated with the mining industry involve the understanding and analysis of fluid or gas flow. Typical examples include groundwater flow, transport of contaminants, heat transfer, explosions, fire development and dust movements. Both experimental work and numerical models can provide the necessary information for solution of any particular problem. The long-term pyrite oxidation, acid mine drainage generation and transportation of the oxidation products are noted to be the most important problems that can be modelled in order to predict the transport of thecontaminants through groundwater and rivers flow systems, to interpret the geochemistry and achieve a better understanding of the processes involved

Probabilistic risk assessment of acid mine drainage generation resulted from chalcopyrite oxidation process within Sarcheshmeh copper mine tailings

A probabilistic predictive method for estimating the risk of acid mine drainage generation within the copper tailings dump of the Sarcheshmeh copper mine, Iran, has been presented in this paper. For this purpose, the input and output parameters were determined after gathering historical data and building an appropriate database. Some of the critical parameters, including depth, and concentrations of bicarbonate, chloride, nitrate, and nitric, were considered input data, while the output parameters were chalcopyrite, pH. The best distribution functions on each input parameter were found by Chi Sq. criteria. Subsequently, the best linear statistical relationships between the input and output data were determined. Then, the best probability distribution functions of output parameters were defined by inserting the input parameters in the obtained linear statistical relationship. The results showed that the remaining chalcopyrite fraction values were between 0.1094 % and 0.2159% at a 90% probability level. In contrast, the pH values would be expected between 3.13 and 8.04 at this probability level

Prediction of fly-rock using gene expression programming and teaching– learning-based optimization algorithm

Peer ReviewedObjectius de Desenvolupament Sostenible::12 - Producció i Consum ResponsablesObjectius de Desenvolupament Sostenible::12 - Producció i Consum Responsables::12.2 - Per a 2030, assolir la gestió sostenible i l’ús eficient dels recursos naturalsPostprint (published version

Application of a geographic information system (GIS) for selecting the location of a coal wastes dump - a case study

The Gheshlagh mining region, which includes more than ten active and several abandoned coal mines, is one of the most significant regions for coal mining in northern Iran. Due to the lack of more suitable ecological and environmental strategies for coal wastes management from these mines, a large amount of wastes has been dumped in the vicinity of the mines. The primary purpose of this research is to propose a new methodology for selecting a site for coal waste piles applying GIS in the Gheshlagh region. For this, the coal waste piles have been firstly detected by field observations and based on environmental aspects. All the required maps, including farmlands, surface streams such as seasonal rivers, forests, and residential areas have been run in the ArcView software package. Finally, the best location of the site for dumping the coal wastes with an area of 27 hectares has been detected and suggested in the Gheshlagh coal region using the IDRISI software package considering environmental and economic aspects. These studies are beneficial for mine planners to reduce the environmental issues nearby the mining operations

The effect of changing confinement diameter on axial load transfer mechanisms of fully grouted rock bolts

This paper aims to study the effect of changing the confinement diameter on the axial load-bearing capacity of rock bolt systems. The diameter of the confinement is monitored in a fully encapsulated rock bolt at day 7 and 28 of grout curing. These particular times were considered critical to demonstrate grout strength when conducting pull-out tests on rock bolt samples. Following this, the samples were cast with a water-grout ratio of 36%, the internal diameters of encapsulation being 23 mm and 50 mm, and the encapsulation length at 50 mm. The results indicated that by increasing the confinement diameter, the rock bolt\u27s load-bearing capacity increased approximately 32% and 45% for days 7 and 28, respectively

Finite element numerical modelling of rock bolt axial behaviour subject to different geotechnical conditions

In rock bolting systems, grout acts as a medium to transfer initiated stress from the bolt to stable rock mass, and also to transfer the in-situ stress from surrounding rock to the bolt-grout interface. In this study interaction between the mechanical characteristics of the grout and rock bolt behaviour was investigated in different confining pressure conditions. First, the uniaxial compression strength of the grouts was experimentally determined, and then pull-out tests were carried out on rock bolts encapsulated using the same grouts to quantify the bonding behaviour. Numerical models using ABAQUS explicit finite element code were then applied to further analyse the effects of mechanical properties of the grouts and the confining stress on the behaviour of the rock bolting systems. The compression of the simulated results with the experimental tests showed that the proposed FE models simulate the axial behaviour of rock bolts efficiently. The results of the parametric study indicated that grout mechanical properties and the level of confining stress affect the ultimate bearing capacity of the encapsulated rock bolts and the force-displacement behaviour. The level of damage that occurred at the specimens due to pull-out load is also significantly influenced by these factors