Abstract: Designing of a stable overburden disposal slope is vital in large opencast coal mines. Spoil generated during extraction of coal which is dumped externally requires larger land to remain stable and also poses problems to surrounding environment due to limited land availability. This has lead to the preference of internal dumping in which the waste is dumped in de-coaled region which is beneficial during extraction and reclamation of mine. Internal dumping is also the most economical and environment friendly method of waste disposal and is being adopted everywhere. It has certain limitations and inherent dangers of failures posing operational and safety threats. In this paper, a numerical study for stability of 80 m high internal dump slopes from an opencast coal mine of Wardha Valley Coal Field, Maharashtra, India has been carried out using Finite Element Method (FEM). Different scenarios as per the dump heights have been accounted and simulated using Plaxis2D-8 to understand the failure mechanism and the changes in factor of safety with variation in bench height and the number of benches.

Abstract: This article describes one of possible approaches to deoxidant cost optimization in steel production, based on the expert system. Education of the system is based on successfully completed heats. Bayesian networks and decision trees are suggested as the mechanisms for knowledge extraction.

Abstract: Seismic wave influence in near field from millisecond delay blast to buildings with different foundation configuration was researched. Three main type of base (square, tree-corner and elliptical shape) were described. Recommendation for charges disposition and orientation in blasting scheme were given.

Abstract: Stability of waste dump is now gaining importance due to increasing depth and size of mine. Management of dump nearby mining areas is one of the most critical and crucial task for mine management due to limited land and other governing laws related to environment and forest conservation. In this paper, a study was conducted to establish the effect of slope angle on the stability of waste dump for accommodation of flyash is carried out. Based on numerical simulation, it was found that the dump slope of 60 m height with 36° slope can be critically stable with 20% flyash randomly mixed with overburden materials whereas flatter slopes provide higher factor of safety. Keeping other parameters constant, the optimum slope of 32° is the best possible to accommodate the mine dump for its long term stability. These findings were further supported by study of maximum velocity vectors and shear strain rates in every case and the extent of damage zone due to tensile pull. It is hoped that this technical note will find utility wherever a design of dump of chosen material type is being planned where the wastes can be managed alongside ulitisation of flyash.

Abstract: Stream sediments play a significant role in geochemistry exploration by identifying possible sources of anomalous element concentration. This work is the baseline stream sediments geochemical study which brings general information on the geochemical dispersion of the metal elements (especially gold) at Gouap-Nkollo prospect (SW Cameroon) with the aim of providing a useful guide for future exploration strategies. For this study a concentration of 47 elements was measured in 10 stream sediment samples using BLEG and ICP-MS methods, but emphasis was given to the following 21 chemical elements: Al, Ca, Fe, K, Mg, Na, P Ag, Au, B, Co, Cr, Cu, Mn, Ni, Ti, Zn, Ce, La Th, U and Zr. Averaged elemental concentration for each samples obtained by statistical analysis showing patterns of enrichment and depletion which may relate to localized mineralization conditions or local lithological changes. Results showed that the stream sediments have high concentrations of Au, Ce and La with average values of 314.85ppm, 19081ppm and 11808ppm respectively for gold, cerium and lanthanum. Cerium and Lanthanum have considerably high concentrations when compared with other Rare Earth Elements (REE) analyzed. These concentrations represent interesting indices for Au and LREE mineralization’s. The geochemical dispersion of the metal elements (especially gold) reveals that high concentrations are recorded in the northern part of the prospect, close to the quartz-tourmaline vein within the quartzite. This result indicates that the Au and other metal elements probably originated from the quartz-tourmaline veins hosted by surrounding rocks. Detailed exploration work including geochemical soil sampling and geophysical survey is highly recommended in the northern part of the Gouap-Nkollo prospect, where anomalous concentrations of Au were observed, for further investigation.

Abstract: Design of coal pillars in a coal mine remains a challenge inspite of several theories proposed by several researchers over a period of time. India is heavily dependent on coal availability for supply of electricity to it’s billion of citizens. This has burdened the coal industry to increase the coal production which ultimately has lead to extraction of coal pillars also. Coal pillars are used to support the overlying roof rock to prevent it from falling. The dilemma with coal pillar stability is that On one hand, the size of the pillar should be as small as possible to enable maximum recovery of coal, while on the other hand, the pillar should be large enough to support the load of overlying strata. The stability of coal pillars has fascinated several researchers and hence many empirical equations have been proposed over the decades. In this paper, parameters like height of pillar, depth of pillar, compressive strength of coal, depth of the coal seam have been taken as input to estimate factor of safety of coal pillar from two mines i.e., Begonia and Bellampalli. It is found that Greenwald (1941), Salamon and Munro (1967), Sheorey (1992) and Maleki (1992) method has estimated failed cases correctly while Sheorey (1992) & Maleki (1992) have not predicted stable case of pillar correctly which is an interesting finding as empirical relations proposed by Sheorey (1992) is assumed to have good prediction in Indian condition.

Abstract: Companiganj is one of the resourceful upazila of Sylhet district, though no gas or oil field have not been found yet, renowned for its hard rock. Hard rock, one of the main geo-resources of Bangladesh after gas and coal, is very useful in construction sector and cement industry. The source of this rock is near Meghalaya of India. This part of India is relatively in higher than the ground level of Bangladesh. That’s why the rock comes down by gravity especially in the rainy season. The water is the main transportation media which brings these rocks. People normally use manual hand tools for rock extraction and use two type of crusher to crush these rocks. In this research paper, we tried to find the economic feasibility of extracting these rocks. Though the extraction method of this quarry is not technologically advanced, but after doing this research, we can say that this quarry is economically feasible.

Abstract: Phosphate industries use bulk amount of concentration H₂SO₄ during production of phosphate fertilizers. Stainless steel is major supporting metal for completion of several processing operational works. This acid produces corrosive effect for stainless steel. It develops corrosion cell on the surface of base metal and it changes its internal morphology as well as physical, chemical, mechanical properties. H₂SO₄ behaves like diabetes for this industrial metal and industries face economical. The eradication of corrosion problems used organic inhibitors like 1-(2-chlorophenyl)methanamine and 1-(2-bromophenyl)methanamine and its inhibition effect and surface coverage area studied at different temperatures 333⁰K, 343⁰K and 353⁰K in presence of 15% H₂SO₄ and 15mM concentration of inhibitors. The corrosion rate of metal was determined by weight loss experiment and potentiostat techniques. The surface adsorption and surface thin film formation were analyzed by application of activation energy, heat of adsorption, free energy, enthalpy and entropy. The inhibition efficiencies and surface coverage areas were shown that the used inhibitors produced anticorrosive effect in acidic medium.

Abstract: The main objective of this study is to reutilize the barely and rice husks (BH & RH) after its conversion to ashes by firing at 600C (BHA & RHA) as replacing materials of Ordinary Portland cement (OPC) to prevent or at least to reduce the problems of air pollution and energy consumption. The results showed that the water of consistency and setting times of fresh cement pastes increased gradually by the addition of either BHA or RHA. Generally, all the studied properties are improved and enhanced with curing time up to 90 days. The combined water content, bulk density, flexural and compressive strengths decreased with curing time up to 3 days, whereas the apparent porosity increased. During the later ages from 3 up to 28 days and then decreased onward, these properties increased, while the apparent porosity decreased. These characters improved and increased only with 16 wt.% BHA or RHA content and then decreased. The free lime content of the OPC pastes increased as the curing time proceeded up to 90 days, while those containing either BHA or RHA increased only up to 3 days and then decreased up to 90 days and then reincreased onward. It was concluded that the higher contents of BHA and RHA (20 wt.%) must be avoided due to its outstanding cementing properties. The FT-IR spectra and SEM images appeared a slight improve in the crystals and microstructures of the newly formed phases.