Geotechnical and Geochemical Assessment of Mine Wastes from Sabah, Malaysia for Biocementation Improvement

Mining wastes are known to be harmful to the environment especially when unregulated, untreated, or abandoned. The first step in their remedial action is the characterization of the geotechnical properties. The aim of this research is to investigate the properties of two Copper mine wastes obtained from Lohan and Bongkud in Sabah, Malaysia, for potential biocementation treatment. The methodology includes soil classification, determination of engineering properties, geochemical properties, and microstructure fabric. Classification results indicated that while both soils can be classified as SM and A-4 according to USCS and AASHTO respectively, Lohan waste has higher coarse-grained particles (69.8%) compared to Bongkud (58.1%). Both soils have a low liquid limit (LL<50), low plasticity (PI <7) and low liquidity (LI<1), and a close range of specific gravity (2.65-2.71). However, Bongkud has higher pH (5.27) and natural moisture content (28.14%) due to its higher organic content (1.27%). In terms of engineering properties, Lohan and Bongkud have MDD at 1640 and 1700 kg/m3 and OWC at 16 and 15%, respectively, with low cohesiveness and a high angle of friction. With hydraulic conductivity, k falls within the range of 10-2 cm/s, and these soils are classified as having a medium degree of permeability. Geochemical analysis indicated the presence of nine heavy metal elements with Pb (0.535 mg/L) and Ni (1.092 mg/L) exceeded the safety level in Lohan and Bongkud, respectively. SEM analysis shows both soils have a high degree of disorientation. In conclusion, both soils can be benefitted from biocementation treatment due to the SM classification, medium degree of permeability, and high heavy-metal contaminations

Hydraulic Conductivity of Mine Waste Treated Using Enzyme-Induced Calcite Precipitation Method Under Various Curing Conditions

The hydraulic conductivity of mine waste soil is considered moderately high attributed to the high percentage of pore spaces. One of the risks associated with this poor property is possible intrusion of contaminated acid drainage into the groundwater or river. Biocementation using enzyme-induced calcite precipitation is relatively new, more inventive, and environmentally sustainable method compared to the other techniques in improving soil properties. However, limited available data on how this method can be applied in improving heavy-metal contaminated mining wastes. This paper summarizes the effect of this treatment include different cementation concentrations, degree of compactions, curing temperatures and curing durations in reducing the hydraulic conductivity of mining waste. Results obtained indicate greater effect of 1.0M compared to 0.5M concentration, degree of compaction of 80% compared to 70%, curing temperature of 25 °C compared to 15 °C and 5 °C, and immediate reaction effect after 1-day then slowed down after 3 and 7-day curing. When compared to control sample, the reduction in hydraulic conductivity is ranging 75.66 to 97.14%. The positive result is attained due to the production of calcite, CaCO3 that biocemented the soil particles together and reduced the pore spaces, indicated by their content obtained ranging 2.0-5.15 % in the treated soil. Visual images through SEM and spectra of x-ray diffraction confirmed the presence of CaCO3 in soil particles. This work contributes significantly to the study of the properties of copper mine tailings in Ranau, Sabah, including the first study on biocementation of copper mine tailings. The method could be used to reduce the hydraulic conductivity of mining waste soils contaminated with heavy metals. Various scenarios such as curing temperature, duration, cementation concentration and degree of compaction have been proposed to optimize the effectiveness of the treatmen

Hydraulic Conductivity of Mine Waste Treated Using Enzyme-Induced Calcite Precipitation Method Under Various Curing Conditions

The hydraulic conductivity of mine waste soil is considered moderately high attributed to the high percentage of pore spaces. One of the risks associated with this poor property is possible intrusion of contaminated acid drainage into the groundwater or river. Biocementation using enzyme-induced calcite precipitation is relatively new, more inventive, and environmentally sustainable method compared to the other techniques in improving soil properties. However, limited available data on how this method can be applied in improving heavy-metal contaminated mining wastes. This paper summarizes the effect of this treatment include different cementation concentrations, degree of compactions, curing temperatures and curing durations in reducing the hydraulic conductivity of mining waste. Results obtained indicate greater effect of 1.0M compared to 0.5M concentration, degree of compaction of 80% compared to 70%, curing temperature of 25 °C compared to 15 °C and 5 °C, and immediate reaction effect after 1-day then slowed down after 3 and 7-day curing. When compared to control sample, the reduction in hydraulic conductivity is ranging 75.66 to 97.14%. The positive result is attained due to the production of calcite, CaCO3 that biocemented the soil particles together and reduced the pore spaces, indicated by their content obtained ranging 2.0-5.15 % in the treated soil. Visual images through SEM and spectra of x-ray diffraction confirmed the presence of CaCO3 in soil particles. This work contributes significantly to the study of the properties of copper mine tailings in Ranau, Sabah, including the first study on biocementation of copper mine tailings. The method could be used to reduce the hydraulic conductivity of mining waste soils contaminated with heavy metals. Various scenarios such as curing temperature, duration, cementation concentration and degree of compaction have been proposed to optimize the effectiveness of the treatmen

Development of slope monitoring device using accelerometer

There are many types of instruments that have been used for monitoring the high risk slopes as a precaution to prevent the loss of lives. Unfortunately, there is no such works of installation slope monitoring instrumentation as detectors and preventive actions before the slope failure. Automatic Wireless Accelerometer Monitoring System (AWAM) is a new device of monitoring system using accelerometer, introduced in this research. It is more efficient than conventional techniques and less expensive. The application and operation of this system does not interrupted by physical obstacles, different climate conditions, and the construction works at site. In addition, no contact is required since the accelerometers are installed on the slope. Consequently, geomorphology limitations are not considered as limitations of the system operation. This paper discusses the sensor database system by AWAM and shows the effectiveness of the device to monitor slope failures and act as a warning sign. It was presented in two parts; the first part consisted of the physical modelling calibration test from sensor database system (AWAM device) and from load cell test while the second part discussed on the numerical model simulated by using software (Slope/W and LimitState) and the data from vane shear test. The AWAM device can be used as a monitoring system to detect soil movements. However, accelerometer was able to give AWAM’s readings if the device is moving in tilting modes

Hydraulic conductivity of mine waste treated using enzyme-induced calcite precipitation method under various curing conditions

The hydraulic conductivity of mine waste soil is considered moderately high attributed to the high percentage of pore spaces. One of the risks associated with this poor property is possible intrusion of contaminated acid drainage into the groundwater or river. Biocementation using enzyme-induced calcite precipitation is a relatively new, more inventive, and environmentally sustainable method compared to the other techniques in improving soil properties. However, limited available data on how this method can be applied in improving heavymetal contaminated mining wastes. This paper summarizes the effect of this treatment, including different cementation concentrations, degree of compaction, curing temperatures and curing durations in reducing the hydraulic conductivity of mining waste. Results obtained indicate a greater effect of 1.0M compared to 0.5M concentration, a degree of compaction of 80% compared to 70%, a curing temperature of 25 °C compared to 15 °C and 5 °C, and immediate reaction effect after 1 then slowed down after 3 and 7-day curing. When compared to control samples, the reduction in hydraulic conductivity ranged from 75.66 to 97.14%. The positive result is attained due to the production of calcite, CaCO3 that biocemented the soil particles together and reduced the pore spaces, indicated by their content obtained, ranging from 2.0-5.15 % in the treated soil. Visual images through SEM and spectra of x-ray diffraction confirmed the presence of CaCO3 in soil particles. This work contributed significantly to the study of the properties of copper mine tailings in Ranau, Sabah, including the first study on biocementation of copper mine tailings. The method could be used to reduce the hydraulic conductivity of mining waste soils contaminated with heavy metals. Various scenarios such as curing temperature, duration, cementation concentration and degree of compaction have been proposed to optimize the effectiveness of the treatment

Soil water characteristic curves of compacted kaolin for various initial moisture content

The soil water characteristic curve (SWCC), also known as soil water retention curve (SWRC), describes the relationship between water content and soil suction in unsaturated soils. The importance of SWCC can be seen, as the relationship affects geotechnical properties such as shear strength, volume change, permeability and deformability of unsaturated soils. This paper presented a preliminary study on the effect of initial water content and the density on SWCC on unsaturated compacted kaolin. Filter paper technique was used for suction measurement on the unsaturated compacted kaolin soil. Filter paper was used to determine total suction and matric suction through contact and noncontact technique. The calibration curve was used to relate with the gravimetric water content obtained in filter paper with corresponding suction. A comparison on SWCC established through filter paper was also compared with that of the axis translation technique (pressure plate extractor). The study found that the initial water content and the density respectively, have great influence on the SWCC of compacted kaolin. However, the combined effect could be seen significantly at lower suction

Implementation of project based learning for civil engineering students at Universiti Teknologi Malaysia

Implementation of Project Based Learning (PtBL) in Universiti Teknologi Malaysia (UTM) as part of Outcome Based Education (OBE) framework have faced various challenges (i.e revamp on the undergraduate co-curricullum, required high commitments from academicians & faculty and facilities to cater PtBL activities). This paper discusses the effectiveness of PtBL teaching method in an effort to develop the students’ soft skills in tandem with the technical or professional competencies; and problems, challenges and potential improvement in the course. The Survey Camp course which is offered at year one of a four years civil engineering degree programme in the Faculty of Civil Engineering (FKA), UTM was chosen for this study. It is a ten days fieldwork in which the students will carry out an engineering survey project from field to finish in groups of five to six students supervised by the academic staff. Assessment of the technical aspects was based on the students ability to meet the minimum engineering surveying’s standard whereas the assesment of soft skills was conducted during various sessions of the survey projects. Survey questionaires were given at the beginning and the end of the course as part of evaluation of the course effectiveness. The research has found that the technical aspects were achievable though with lesser degree for the engineering design. However, on the soft skills, students demonstrated an overall improvement of competency but it was difficult to determine the levels for the average students while the best and poor performers were easily observed

Innovative design of survey camp course for civil engineering program

This paper seeks to present the innovative design of the Survey Camp course for the civil engineering program at the Faculty of Civil Engineering, Universiti Teknologi Malaysia. The Survey Camp is designed as a ten day on-campus training which consists of surveying activities such as levelling, traversing and detailing. It also introduces the usage of the latest surveying tools and technologies used in typical civil engineering projects. This course allows the first year students to experience practicing engineers’ working environment in relation to surveying activities. The learning environment of the Survey Camp was converted from the traditional learning approach to student-centered learning via project-based learning since 2012 with several improvements and modifications. Furthermore, the implementation of Project Based Learning as the teaching and learning approach enhances the students’ knowledge and soft skills. Problem solving skills pertaining to civil engineering tasks and the development of soft skills such as team-working, leadership and communication skills are addressed. Assessments and feedbacks from the academic start and students were used as tools to evaluate the outcomes of the course. Recently, this course has produced a module and online assessment tools. This module and assessment tools have also been implemented at other universities, namely, UTHM (assessment tools since 2015), UMP (module, 2012 and assessment tools since 2016) and currently at UNIMAS (assessment tools). The implementation of the project based learning as a learning environment in conducting the Survey Camp course has successfully shown that the students’ attainment in developing the selected engineering professional and soft skills is enhanced

Using soil water characteristic curve in computing unsaturated hydraulic conductivity of compacted tropical soil

Contaminants flow through compacted soil liners and coversare usually considered under saturated conditions during design stage. Whereas, the compacted soil barriers in reality are neither completely saturated nor completely dry, rather they are in an unsaturated state. Thus, unsaturated flow principles need to be properly simulated to determine the contaminant flow through compacted soil barriers in order to protect groundwater. Soil water characteristic curve (SWCC) which is the relationship between soil suction and water content is the main modeling parameter of unsaturated soil. This paper evaluates the SWCC data of a tropical laterite soil used as a liner material in sanitary landfill. The effect of gradation with respect to fines content on the dry of optimum, optimum and wet of optimum moisture contents on SWCC were investigated. Laboratory tests using pressure plate apparatus were conducted to determine the variation of volumetric water content with soil suction for a pressure range of 1 kPa to 1000 kPa. The experimental SWCC data were fit to the Brooks and Corey parametric equation to compute the unsaturated hydraulic conductivity. Based on the SWCC data, greater air entry suctions were obtained for specimens with higher fines contents when compacted wet of optimum moisture content and the water retention capacity increased with increase in fines content. Using the SWCC, the unsaturated hydraulic conductivities of the soil liner used in simulating leachate migration were computed