Can you help me with a paraphrasing these as soon as possible? and try to make it shorter as you can. Thank you.
1. Discussion part
Hazards were defined based on the interpretations made and the datasets given. The geological risks that are determined are best defined as any type of lithological ambiguity that could pose dangerous stresses on the structural integrity of the rock. It has been determined that open-cut mining would be deemed economically insufficient due to the lack of total coal thickness, overburdened Upper seam, and depth of coal layers. This varies throughout the boreholes but shows a maximum thickness of around 7-8 meters. The brightness profile of the GM seam drill core also indicated higher quality coal at greater depths perhaps due to less exposure to compaction fracturing and oxygen. The GM seam also exhibited no major fracturing/jointing. Underground mining would be effectively suited to mine the coal at the given depth. The hazards of such an operation have been outlined in relation to sedimentary features and units seen.
The height of the coal seam is an important factor when implementing mining operations. It shows areas that are viable for removal. The Geological Hazard map deduces three major areas considered for underground processing. A punch longwall mine is probably best suited to mine the given coal. At the thickest part of the coal seam, the height of the longwall could reach a conservative 5meters. The wastage from the drilling operations could result in 1-2meters of material. The longwall would be positioned as low as possible in the seam so that the lower grade roofing can be left behind. Roof supports will have to be determined based on the consistency of the roofing material. Volatile matter and gas concentration would need to be closely monitored. In addition to this, any major fracturing or jointing/cleating that is found needs to be assessed immediately. If deemed necessary due to possible caving other methods can be implemented ie Board and Pillar mining that leaves sufficient support while extracting higher grade coal from retreats.
One of the three major areas defined in the Geological Hazard map is a shallow region of the GM seam. When mining this region the stratigraphic units above and below need to be considered when choosing drill equipment. The density profile of these layers (including dykes and intrusions) is substantially different allowing for sparks to occur while using lower density drill pieces. Gas would also need to be closely monitored and possibly vented/bled. Mudstone units would need to be carefully mined to reduce powder/dust exposure and may require water saturation. The thin mudstone layers can also attribute to a roof collapse if stresses applied from the longwall structure and weight. If any lower density units are found in the floor (ie mudstone or coal) they need to be assessed immediately as crushing can occur along with localized subsidence. Mudstone can also become muddy when exposed to water saturation methods.
The region of the GM seam to be mined is under the influence of tectonic factors that influence north-east localized faulting. The structural units seen are thrust faults, normal faulting, and slickensides. The Geological Hazard map presents the array of structures present including sandstone bodies for roof support. The thrust faults seen have relatively low throw with around 1-7 meters of movement. These three smaller faults (north, south, and at the center of the bottom) can be responsible for hazardous wedge failures. These hazards can be avoided or managed when confronted but can displace substantial amounts of rock. However, the normal faults are seen - even though it may have a higher throw - do not create many hazards when being confronted underground. This could be due to the stresses of normal faults propagating laterally, parallel to the horizon. When other stresses of rock facies present are calculated the normal faults will need to be considered for the overall integrity of the longwall structure. Finally, the slickensides seen occurred at the time of deposition when the displacement of the layers may have occurred due to a change in elevation or burial. The structural unit is formed when these layers are subject to stresses that cause weaknesses across the planes. When pressure is applied or removed the slickensides can fall easily due to the already-present weaknesses. These features have been plotted on the map and define the hazards present.
Analyses of the depositional environment may have assisted in the original determination of the drill core locations. It could be interpreted that the locations picked were indicative of an underlying sedimentary structure. The areas chosen coincidently show the varying depths which could have been determined by an interpretation of its depositional environment. The presence of paleochannels and massive sandstone bodies could confirm the presence of this river system/deltaic environment. "...Depositional modeling can be used to predict large-scale trends in coal deposits on a regional scale and are therefore useful in the initial phases of coal exploration. Further, small-scale variations in coal thickness, quality, and lateral continuity frequently can be predicted, providing data that can be extremely valuable in mine planning and development..." (Ward, n.d).
2. Environment impacts
When a new mine is set up to extract coal it has to adhere to regulations imposed by the Environmental Protection Agency (EPA). Waste and tailings have to be managed and contained to prevent contamination of the environment and food sources. Geological features like Aquifers need to be located in relation to prospective sites. Depending on the type of mine and location other factors like transport-related dust pollution need to be considered. "...Australia's international obligations under the agreement reached at the United Nations Conference on Environment and Development (UNCED June 1992) give EPAs permission to use the precautionary principle — that an action should not be taken if the consequences are uncertain and likely to be dangerous to the public or the environment — in their assessments. This is rarely if ever, invoked in the case of approving new coalmines...."(Castleden, 2011). This is indicative of the scale of the environmental impact of new coal mines in Australia in 2011.
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