Applied Mechanics and Materials Vol. 920

Abstract: This paper describes the results of a field investigation with the objective of evaluating the possibility to produce drone-derived 3D digital point clouds sufficiently dense and accurate to determine the rock mass rating (RMR) in the underground mine in Bukit Kachi. Agisoft Photoscan software was used for producing the three-dimensional points cloud from the two-dimensional images' sequences. The rock mass rating was evaluated by using Discontinuity Set Extractor (DSE) and Dips 7.0 in Rockscience software. Results from this research show that 3D digital point clouds, derived from the processing of drone-flight images, were successfully used for reliable representation of discontinuity of the tunnel. According to the results of the analysis, both Tunnel A and Tunnel B are classified as "fair rock." Meanwhile, Tunnel A is failing due to geological conditions of feldspar decomposition that are classified as class I, which is "very poor rock." According to Dips 7.0 analysis, the major direction of discontinuity set of Tunnel A for Window right is N300 – N310, while for Window left is N350 – N360. The most dominant discontinuity direction for Tunnel B Window right is N340 – N350, and the orientation for Window left is N10 – N20. When manual mapping and DSE analysis are compared, both orientations of the discontinuity do not give the same direction due to less data reading in the field and high accuracy from the software.

Abstract: Sarawak located in Borneo is endowed with the vast availability of peat water sources, particularly for the state southern region. Several investigations have shown that electrocoagulation treatment with aluminium electrodes is feasible to treat peat water in which the quality is comparable to the National Water Quality Standard (NWQS). Even though electrocoagulation treatment is feasible to treat peat water, the characteristics of peat water electrocoagulation flocs have not been reported. As such, this study aims to investigate the characteristics of the electrocoagulation flocs from peat water derived from the Sarawak southern region by using batch electrocoagulation treatment. The objectives of this study are to conduct an experimental study analysis of and identify the minerals on the electrocoagulation flocs along with operating energy cost analysis of peat water batch electrocoagulation treatment. Consequently, this study has found that reaction time and current density affect the production of flocs in which the amount of flocs increases with the increasing reaction time and current density. The flocs produced are found to consist of a large fraction of oxygen (O), carbon (C), iron (Fe), and aluminium (Al) along with a small fraction of potassium (K), magnesium (Mg), calcium (Ca) and Silicon (Si). The presence of Al observed in the flocs is due to the aluminium hydroxide generated during the electrocoagulation process. The total operating cost for peat electrocoagulation with a current density of 5A and reaction time of 20 minutes is about RM0.31 per m³. As a result, the electrocoagulation of peat water process is able to treat peat water as well as produce flocs in which earth elements and heavy metals could be recovered.

Abstract: The formation of the Air Piau Gold Deposit in North-East Peninsular Malaysia due to Permo–Triassic subduction and collision between Sibumasu and East Malaya blocks and resulted in several phases of deformation, contraction, and metamorphism. Kinematic and petrography study of quartz veins in Air Piau area observed whether following the foliation of metamorphic rock or crosscut the foliation. Early generation of veining system in Air Piau follow the host rock foliation (V1). Meanwhile the later formation of the hydrothermal vein has a cross-cutting relationship with foliation (V2). Some veins observed were sheared and brecciated (V3). Positive correlation between Au and As concentration that can be characterized these deposit formed at mesozonal zone. V3 vein type showed the brecciated texture of vein indicates the brittle structure deformation. The conceptual model of orogenic gold, this type of V3 vein can be classified as epizonal zone. Regionally, the Air Piau gold deposit shares geologically similarities (in term of tectonic setting, geological structures controlled, host rock, ore gechemistry) with many other sediment/metasediment- hosted, orogenic gold deposits in Peninsular Malaysia such as Tersang, Selinsing and Penjom. Furthermore, Air Piau gold deposit characteristics as discussed before supported the theory related with orogenic/mesothermal gold from various researchers However, a number of inferences on classified Air Piau gold deposit model as orogenic gold deposit remains speculative in the absence importance data like ore geochemistry data (Hg, Sb and Te element concentrations) and fluid inclusion data.

Abstract: The rich karstic limestone aquifer in Kinta Valley, Perak is a potential resource of clean water in the future when the surface water resources will deplete and insufficient to support the growing population. A proper preliminary evaluation of groundwater hydrogeochemistry is essential for knowing the proper application and maintaining the available groundwater as a sustainable resource. Four production wells in Kinta Valley are sampled and analyzed for physicochemical parameters from 2018 to 2020. In this study, major chemical compounds, pH, total hardness (TH), and total dissolved solids (TDS) are interpreted to construct Piper’s trilinear diagram and Gibbs plot which describe the hydrochemistry of the samples. Drinking Water Quality Standard from the Ministry of Health Malaysia (MOH) and the United States Environmental Protection Agency (US EPA) National Primary Drinking Water Regulation is used as guideline standards for water quality evaluation. Based on the results from this study, the quality of groundwater in Kinta Valley is healthy and has the potential to be used as drinking water besides using as irrigation water. The predominant hydrochemical reaction of the groundwater is found to be a bicarbonate-calcium-magnesium reaction, which shows the aquifers are in contact with the subsurface karst system as the main ions originated from the dissolution of carbonate bedrocks.