In the past, much of the petrophysics done in the Australian mining industry has been based upon gamma ray, simple density devices, resistivity, and televiewers. Common uses of petrophysical data include locating the top and bottom of the seam/ore, determining the water level, mapping fractures and faults, computing hardness, and facies analysis. However, the industry is moving toward more advanced applications, such as improved methods of understanding the porosity and permeability of the rocks, 3D mapping of stability, and the use of petrophysical measurements as a cost-effective means of supplementing or even replacing traditional assay methods.
This paper begins with a brief introduction to the mining environment as compared with the modern oilfield environment. While petrophysical data acquisition in East Australian coal mines is not so far removed from shallow oilfield land wells, open pit mines, such as the Pilbara Iron Ore fields of Western Australia are a very different world - thousands of holes are drilled, each generally less than 60 metres. Assays (geological analysis of material collected from the hole) are the primary reference data. Costs to log are low and many processes (data interpretation, delivery of logs, etc.) are automated.
Next we will review how gamma ray, density, neutron, resistivity, and caliper measurements are used throughout the Australian mining industry, paying some attention to the challenges of using classic tool designs such as 16/64 normal resistivity tools and single point (uncompensated) density. Sonic, electrical imaging, and optical televiewers are the next tier of measurements, used for fracture/fault mapping, ground stability, hardness and seismic integration. Finally, we will discuss the latest wave of technologies to be gaining ground in the Australian mining market, including NMR, VSP, and elemental spectroscopy.
The introduction of advanced petrophysical measurements in Australian mining is opening the door for exploiting new applications, many centered around “big data” or machine learning techniques, such as automated facies identification, high resolution mapping of both major and minor minerals, and 3D visualisation of ore properties.
The American Institute of Mining, Metallurgical, and Petroleum Engineers (AIME) has released a report titled, “In Pursuit of Technological Innovation,” that outlines the goals and initial analysis of the AIME Council of Excellence. An overview of honors and awards SPE members are eligible for from SPE’s founder society American Institute of Mining, Metallurgical, and Petroleum Engineers (AIME), United Engineering Foundation, and American Association of Engineering Societies. The American Institute of Mining, Metallurgical, and Petroleum Engineers (AIME) is the parent organization of SPE. AIME fulfills its legacy by supporting member societies’ programs and awards, and by documenting the history of the industries and technologies.
Deng, Song (Changzhou University) | Liu, Yali (Changzhou University) | Wei, Xia (No. 2 Gas Production Plant, Changqing Oilfield Company, PetroChina) | Tao, Lei (Changzhou University) | He, Yanfeng (Changzhou University)
Phase change, a major factor that restricts the development of gas hydrate, is likely to cause blockage in well completion section (sieve section - wellbore lifting section), thus resulting in the engineering losses. In view of the defects in the previous studies on the confluence mechanism of completion section of gas hydrate pressure drop method mining under openhole completion technology, the flow of gas hydrate in the well completion section was simplified as the Main-Branch pipe confluence model in this paper. Firstly, a physical model was established. On the basis of the energy conservation law and the Peng-Robinson equation, the temperature and pressure coupling model was also derived. Then, the Fluent software was used to simulate the temperature gradient and pressure gradient changes in the Main-Branch model. The gas hydrate phase diagram and PT environment under different velocity were obtained. Finally, the contrast analysis between theoretical model and numerical simulation was carried out and the established model was verified. Through the study of this paper, it is possible to prevent blockage of the well completion section by means of depressurization, which can provide theoretical guidance for the control of pressure drop when gas hydrate is extracted by depressurization. It is important for the exploitation and continuous production of gas hydrate in the later stage.
Data bases of numerous oil and gas companies embrace very promising potential for more informed decision-making processes. Furthermore, there is an exponential growth in the influx of generated data from an escalating parade of systems encompassing Enterprise Resource Planning (ERP), machine instrumentation, sensory networks, and escalating mixed-media and different unlabeled data. Despite that, extracting meaningful value from zettabyte-sized datasets remains problematic given the uncontrollable wealth of data and its subsequent noise caveats. Amongst those data warehouses, are a multitude of textual information. Accordingly, Text mining has garnered worldwide interest, as it is a crucial phase in the process of knowledge discovery automatically extracting unstructured to semi-structured information. The following survey covers Text Mining methods and approaches to explain their effectiveness in information retrieval from textual databases from various sources. Moreover, the situational types where each technique may be beneficial are explored.
Nazarova, Larisa A. (Institute of Comprehensive Exploitation of Mineral Resources Russian Academy of Sciences) | Zakharov, Valerii N. (Institute of Comprehensive Exploitation of Mineral Resources Russian Academy of Sciences) | Nazarov, Leonid A. (Institute of Comprehensive Exploitation of Mineral Resources Russian Academy of Sciences) | Shkuratnik, Vladimir L. (Institute of Comprehensive Exploitation of Mineral Resources Russian Academy of Sciences)
The analysis of microflaws on the surface of rock specimens subjected to diametrical compression (Brazilian test) reveals a statically relevant spatial and temporal connection between the surface damage and the level of the external load. Using the developed approach to interpretation of random and deterministic data, the retrospective study of induced seismicity in the operating mining enterprise is performed. Correlation analysis of space-time distribution of induced seismicity parameters and stresses in mine permits to find statistical relationships between the variation of stress field characteristics and the number of seismic events in different parts of an object. This provides a way to predict the induced seismicity parameters in course of mining.
Comprehensive approach to reconstruction of stress fields in rock mass at any stage of mining was offered and realized for Zapolyarnaya coal mine. The approach involves: lab test of rock for finding an empirical dependences of longitudinal velocity on stresses; straight-ray tomography taking impulses of dynamic events as the sounding signals; solution of inverse problem “determination of horizontal components of external stress field when the input data is the velocity field reconstructed by tomography”. It appeared that coefficient of earth pressure equals to 0.6 in the line of mining and 0.45 in orthogonal direction.
Assessment of seismic risk and prediction of mine seismicity are the indispensable components of hard mineral mine planning and design (Durrheim et al, 2007; Leslie, 2013; Hirata et al, 2007). All mines (Hudyma and Brummer, 2007; Zhenbi and Baiting, 2012) and other business entities (Xu et al, 2007) operate microseism monitoring systems (MMS) which collect and process acoustic data. Interpretation of acoustic data in the seismic risk estimation uses statistic methods of “big” seismology, as a rule (Mendecki, 1993; Hardy, 2003), and the criterion of damage accumulation (Kuksenko, 2005). With few exceptions (Al Heib, 2012), the information on the stress state is left aside. In the meanwhile, numerous laboratory experiments (Mogy, 2006; Rao, 2012; Wang et al, 2013) exhibit a statistically relevant dependence between the microdefectiveness D and uniaxial stress level in a specimen. However, the univocal connection of D and stresses under triaxial or polyaxial loading yet remains to be revealed.
The overlying strata is often destroyed in large-scale during shallow coal seam mining, and the sliding instability of the caved roof seriously threatens the safety of the mining field. Based on the monitoring data of the roof weighting of a typical shallow coal mining, the load distribution characteristics of the roof along the strike and trend of the mining field were analyzed, and the mechanical model of the pressure-arch in the surrounding rock was established. Then the evolution characteristics of the pressure-arch and the elastic energy of the surrounding rock were revealed during shallow coal mining by theoretical analysis and numerical simulation. The results show that the continuous pressure-arch was formed when the horizontal stress exceeded the primary vertical stress of the mining field, and the elastic energy of the roof was released by the mining unloading effect. The caved zone of the overlying strata was formed below the inner boundary of the pressure-arch. The elastic energy was accumulated in the pressure-arch and the energy arrived the highest at the front arch foot. The accumulated energy at the arch foot was released by coal mining and the shear zone could be formed. So the sliding of the caved zone along the shear zone would induce the strong roof weighting. The concentrated stress and the released energy during each mining increased with the panel advancing, and the height of the shear zone also increased. The conclusions obtained in the study are of important theoretical value to direct the similar engineering practice.
The instability of overlying strata during shallow coal mining, such as the large-scale roof falling and step-like ground subsidence, is a key problem that can restrict the safety mining in the mines (Ju &; Xu 2015). The self-bearing structure of the pressure-arch can form in the overlying strata after the coal mining, and this structure can support the load of the upper strata and soil layer, so the weighting intensity of the panel is determined by the caved rock in the unloading zone under the inner boundary of the pressure-arch. A large amount of elastic energy is accumulated in the pressure-arch under the concentrated stress, and the released energy for mining is the internal cause of rock failure (Wang et al. 2017). It is an important problem to reveal the distribution characteristics of the stress and energy fields in the mining field, and to analyze the stability of the overlying strata during shallow coal mining based on the evolution characteristics of the pressure-arch.
The extraction of geothermal energy, in situ minerals, liquid and gas hydrocarbons, and subsurface water are all constrained by the flow of fluid through fractured media in the earth’s crust, as is the viability of projects involving CO2 sequestration, nuclear and hazardous waste storage, hydrocarbon storage, and subsurface cavities. Subsurface fractures are the main fluid pathways as the matrix permeability is negligible in most rocks. In situ recovery (ISR) or in situ leaching (ISL), particularly in hard rock, poses some challenges currently. One of the main problems is the modelling of fluid flow in fractured rock masses, and this was the primary focus of this project. Modelling fluid flow in fractures can be done in many ways. The modelling showed that ISL in hard rock demonstrates potential. However, the modelling also exhibited the need for advancements in the fluid flow in fractures modelling area. In this paper comprehensive review of developed approaches for subsurface fracture mapping, processing and characterisation to build a fractured rock mass geometry and fluid flow simulation and mineral leachability along with examples were illustrated.
The extraction of geothermal energy, in situ minerals, liquid and gas hydrocarbons, and subsurface water are all constrained by the flow of fluid through fractured media in the earth’s crust, as is the viability of projects involving CO2 sequestration, nuclear and hazardous waste storage, hydrocarbon storage, and subsurface cavities. Also, fluid flow through fractured media affects the health and stability of the subsurface environment, and the populations that live above. Subsurface fractures are the central fluid pathways as the matrix permeability is negligible in most rocks. So, the presence and nature of subsurface fractures play a fundamental role in many human activities.
Mining in future will be more challenging, because of declining ore grades associated with deeper mining and finely disseminated target minerals in heterogeneous ore bodies, as well as complex mineral association with gangue material, often in locations that are difficult or risky to access. In many areas, ore grades declined by almost 50% over the last 30 years, making mineral processing mostly uneconomical for such minerals. Under these circumstances, innovation in in situ recovery could be a suitable alternative to unlocking resources. The idea of in situ recovery first started with solution mining to extract salt, potash or other minerals as shown in Figure 1(a). It was subsequently developed for recovery from porous media such as sedimentary soil and rock or heavily jointed rock masses as illustrated in Figure 1(b). In situ recovery from porous media has become well established during the last few decades, owing to the presence of void spaces and their connectivity, which facilitate fluid flow from injection wells to recovery wells. In situ recovery of target metals from hard rock is challenging, due to a lack of knowledge about fracture conditions, their connectivity and consequently rock mass conductivity and target metal recoverability, as shown in Figure 1(c).
An area consisting of UG2 Spit Reef provided a unique challenge to extract the reserves by means of a safe and feasible mining strategy. The proposed strategy was required to ameliorate the exposure of personnel to geotechnical risk whilst providing a feasible scenario from a cost perspective.
The initial full channel mining strategy would extract the reserves at stoping widths in excess of 2.0 m at perceived low levels of risk and low grade. A paradigm shift was required to deviate from this historic method.
The proposed mining strategy entailed undercutting the internal waste layer resulting in the extraction of the UG2 reserves at stoping widths of less than 1.2 m at quantified low risk levels and high grade. No successful attempts had previously been recorded where the UG2 Split Reef had been undercut within a highly discontinuous rock mass area such as the Spruitfontein Fault zone. This resistance to change was devolatilized by the introduction of a rigid areal support medium concomitant with several other support unit alterations. This was nevertheless received with negative criticism by a mining team intent on resisting change. The benefit though of extracting the bottom reef portion exclusively, even with inflated support costs resulted in a beneficiated grade (channel grade) to in excess of 6.0 grams per tonne processed versus the 2.6 grams per tonne from the full channel mining extraction strategy.
The proposed mining method and support strategy was presented in March of 2015 and implemented in March of 2017. This paper intends to share the findings pertaining to geotechnical design, support performance and design back-analysis from monitoring results.
Lonmin Platinum Marikana operations are situated along the Western limb of the Bushveld Igneous Complex in the North West Province of South Africa. Karee 3 Shaft (K3) is the largest of the 12 shafts on the Lonmin Marikana lease area. The shaft is able to hoist on average 12 400 t of UG2 and Merensky ore per day (285 200 t per month). The shallower reserves of both Merensky and UG2 Reefs have nearly been depleted and what remains (Fig. 1) are the reserves along both the eastern and western boundaries of the shaft as well as the deeper reserves (825 m below surface) along the sub-decline. Both reef bodies dip from South to North on average 11° with the Merensky Reef overlaying the UG2 Reef (145 m separation). The Spruitfontein Fault can be seen along the western boundary of the shaft (Fig. 1). This fault consists of 2 major faults in conjunction with several sympathetic faults and associated jointing concentrated in an area colloquially referred to as the Spruitfontein Fault zone. The western UG2 Reef horizon is also affected by the presence of Iron Rich Ultramafic Pegmatiod (Fig. 1 - IRUP indicated in maroon which is mostly unmined) and Split Reef (indicated in blue). Pothole features (indicated in yellow) that displace the reefs are also prevalent over the entire K3 shaft property along both UG2 and Merensky horizons.
Ground control condition is one of the most important issues in mechanized longwall mining. The Alpu lignite field in Turkey presents a challenging situation because of its thick, weak and clay content surrounding strata. The purpose of this study is to figure out the ground control condition of the study area by the following steps: classification of the geotechnical units, rock mass classification, cavability index, required shield capacity and floor bearing capacity. Geotechnical classification of the strata layers and rock mass classification was determined by the lithology of the boreholes and laboratory test analyses of them. Caving behavior of the roof strata was predicted by the polish scientists method. Then by applying the “US National Institute for Occupational Safety and Health (NIOSH)” roof rating system at possible roof strata, results were compared. Roof strata were classified as “immediately caving” strata in all production alternatives. Required shield capacity was estimated by detached block method. The caving height was calculated based on the bulking factor of the lignite and roof strata. Low strength floor strata act as a limitation to mining height increasing in all production alternative. Possible mining height was determined as five and six meters with the LTCC method. Required shield capacity in each production alternative was raised by increasing cutting height. To avoid failure during the production, supports should be advance with pressure by touching the roof and soon after the cutting. In addition, cutting height should be limited to the critical height.
Since the 1980; longwall mining has become rival to many surface mining operation performances by achieving more safety, high production and most productive in underground coal mining (Galvin, 2016). The longwall mining method is preferred for stratiform and flat lying orebody and orebody dip needed to be less than 20°. Under the hydraulic roof support, coal is cut with shearer and the broken cut coal is loaded by armored face conveyor (AFC) to the belt conveyor which is parallel to the face advance (Brady and Brown, 1985).
Longwall top coal caving (LTCC) is a comparatively new method for mining thick coal seams. LTCC currently has reached high production and efficiency in longwall mining mostly in China. The procedure is almost the same as the traditional longwall mining method. The Shearer cuts coal seam from the lower section of it onto AFC that installed near the cutting face and in front of the hydraulic support. A rear conveyor belt is added behind the support in the modern LTCC, so the caved coal in the upper part of the seam can flow to the rear conveyor from the canal which is controlled by the rear canopy of the support (Alehossein and Poulsen, 2010). A schematic model of the top coal caving method is illustrated in Fig. 1.
Everyone in our industry is familiar with SPE and its contributions to the industry. But not many know that SPE has a parent organization: AIME, the American Institute of Mining, Metallurgical and Petroleum Engineers. AIME was established in 1871 in Wikes-Barre, PA as the American Institute of Mining Engineers. In 1904, AIME became one of the founder societies along with the American Society of Mechanical Engineers (ASME), and the American Institute of Electrical Engineers (AIEE, later IEEE) to form the United Engineering Society. In 1912, the Iron and Steel Division was created, and in 1918, the American Institute of Metals joined AIME, and the new organization, while still AIME, was called the American Institute of Mining and Metallurgical Engineers.