Annual report of research progress

The mineral and human resources of a state and/or nation are to a large extent the basis of a strong and flourishing economy. In Alaska this is currently illustrated by the activities of the oil and gas industry and the resulting large sums of money that have gone into the state Treasury to help give a sound financial basis to Alaska. The Mineral Industry Research Laboratory has concentrated its efforts on research that will help in the more complete utilization of Alaska's mineral resources for work in the state's mineral industry. This report describes in moderate detail the projects that have been undertaken. These are in the areas of mineral economics, exploration, mining, mineral benefication, beach and ocean mining, utilization of nonmetallics, use of coal resources, and the solving of numerous' specific problems posed by mining people of the state. Training of young men and women for the mineral industry is stimulated by their having the opportunity to work on projects as a part of their graduate program under the supervision of the staff of MIRL. Theses completed offer a considerable amount of information to the public. Recent completed theses are listed in this report. The laboratory has been supported financially by the state of Alaska and various grants and work in kind from individuals and agencies. Private industry has helped in purchasing equipment and cooperative projects are underway with government agencies. Personnel and facilities of the College of Earth Sciences and Mineral Industry supplemented by other professional personnel are involved in teaching and research as set forth in enabling legislation for the Laboratory. The Staff MIR

Geophysical characterization of derelict coalmine workings and mineshaft detection: a case study from Shrewsbury, United Kingdom

A study site of derelict coalmine workings near Shrewsbury, United Kingdom was the focus for multi‐phase, near‐surface geophysical investigations. Investigation objectives were: 1) site characterization for remaining relict infrastructure foundations, 2) locate an abandoned coalmine shaft, 3) determine if the shaft was open, filled or partially filled and 4) determine if the shaft was capped (and if possible characterize the capping material). Phase one included a desktop study and 3D microgravity modelling of the relict coalmine shaft thought to be on site. In phase two, electrical and electromagnetic surveys to determine site resistivity and conductivity were acquired together with fluxgate gradiometry and an initial microgravity survey. Phase three targeted the phase two geophysical anomalies and acquired high‐resolution self potential and ground penetrating radar datasets. The phased‐survey approach minimised site activity and survey costs. Geophysical results were compared and interpreted to characterize the site, the microgravity models were used to validate interpretations. Relict buildings, railway track remains with associated gravel and a partially filled coalmine shaft were located. Microgravity proved optimal to locate the mineshaft with radar profiles showing ‘side‐swipe’ effects from the mineshaft that did not directly underlie survey lines. Geophysical interpretations were then verified with subsequent geotechnical intrusive investigations. Comparisons of historical map records with intrusive geotechnical site investigations show care must be taken using map data alone, as the latter mineshaft locations was found to be inaccurate

Long term time-lapse microgravity and geotechnical monitoring of relict salt-mines, Marston, Cheshire, UK.

The area around the town of Northwich in Cheshire, U. K., has a long history of catastrophic ground subsidence caused by a combination of natural dissolution and collapsing abandoned mine workings within the underlying Triassic halite bedrock geology. In the village of Marston, the Trent and Mersey Canal crosses several abandoned salt mine workings and previously subsiding areas, the canal being breached by a catastrophic subsidence event in 1953. This canal section is the focus of a long-term monitoring study by conventional geotechnical topographic and microgravity surveys. Results of 20 years of topographic time-lapse surveys indicate specific areas of local subsidence that could not be predicted by available site and mine abandonment plan and shaft data. Subsidence has subsequently necessitated four phases of temporary canal bank remediation. Ten years of microgravity time-lapse data have recorded major deepening negative anomalies in specific sections that correlate with topographic data. Gravity 2D modeling using available site data found upwardly propagating voids, and associated collapse material produced a good match with observed microgravity data. Intrusive investigations have confirmed a void at the major anomaly. The advantages of undertaking such long-term studies for near-surface geophysicists, geotechnical engineers, and researchers working in other application areas are discussed

Material studies related to lunar surface exploration. Volume 2 - Application of geophysical and geotechnical methods to lunar sites exploration Final report, 6 Mar. 1967 - 30 Jun. 1968

Geophysical and geotechnical methods for lunar landing site soil property studie

USING NON-BLASTING TECHNOLOGIES FOR DESTRUCTION OF HARD ROCK IN SURFACE MINING

Determination the effective application field of non-blasting technology and technologies for the hard rock preparation for excavation during surface mining

Unravelling the relative contributions of climate change and ground disturbance to subsurface temperature perturbations: Case studies from Tyneside, UK

When assessing subsurface urban heat islands (UHIs) it is important to distinguish between localized effects of land-use change and the impacts of global climate change. However, few investigations have successfully unraveled the two influences. We have investigated borehole temperature records from the urban centres of Gateshead and Newcastle upon Tyne in northeast England, to ascertain the effects on subsurface temperatures of climate change and changes in ground conditions due to historic coal mining and more recent urban development. The latter effects are shown to be substantial, albeit with significant variations on a very local scale. Significant subsurface UHIs are indeed evident in both urban centres, estimated as 2.0 °C in Newcastle and 4.5 °C in Gateshead, the former value being comparable to the 1.9 °C atmospheric UHI previously measured for the Tyneside conurbation as a whole. We interpret these substantial subsurface UHIs as a consequence of the region’s long history of urban and industrial development and associated surface energy use, possibly supplemented in Gateshead by the thermal effect of trains braking in an adjacent shallow railway tunnel. We also show that a large proportion of the expected conductive heat flux from the Earth’s interior beneath both Gateshead and Newcastle becomes entrained by groundwater flow and transported elsewhere, through former mineworkings in which the rocks have become ‘permeabilised’ during the region’s long history of coal mining. Discharge of groundwater at a nearby minewater pumping station, Kibblesworth, has a heat flux that we estimate as ∼7.5 MW; it thus ‘captures’ the equivalent of roughly two thirds of the geothermal heat flux through a >100 km2 surrounding region. Modelling of the associated groundwater flow regime provides first-order estimates of the hydraulic transport properties of ‘permeabilised’ Carboniferous Coal Measures rocks, comprising permeability ∼3 × 10−11 m2 or ∼30 darcies, hydraulic conductivity ∼2 × 10−4 m s−1, and transmissivity ∼2 × 10−3 m2 s−1 or ∼200 m2 day−1; these are very high values, comparable to what one might expect for karstified Carboniferous limestone. Furthermore, the large-magnitude subsurface UHIs create significant downward components of conductive heat flow in the shallow subsurface, which are supplemented by downward heat transport by groundwater movement towards the flow network through the former mineworkings. The warm water in these workings has thus been heated, in part, by heat drawn from the shallow subsurface, as well as by heat flowing from the Earth’s interior. Similar conductive heat flow and groundwater flow responses are expected in other urban former coalfield regions of Britain; knowledge of the processes involved may facilitate their use as heat stores and may also contribute to UHI mitigation

Methane Mitigation:Methods to Reduce Emissions, on the Path to the Paris Agreement

The atmospheric methane burden is increasing rapidly, contrary to pathways compatible with the goals of the 2015 United Nations Framework Convention on Climate Change Paris Agreement. Urgent action is required to bring methane back to a pathway more in line with the Paris goals. Emission reduction from “tractable” (easier to mitigate) anthropogenic sources such as the fossil fuel industries and landfills is being much facilitated by technical advances in the past decade, which have radically improved our ability to locate, identify, quantify, and reduce emissions. Measures to reduce emissions from “intractable” (harder to mitigate) anthropogenic sources such as agriculture and biomass burning have received less attention and are also becoming more feasible, including removal from elevated-methane ambient air near to sources. The wider effort to use microbiological and dietary intervention to reduce emissions from cattle (and humans) is not addressed in detail in this essentially geophysical review. Though they cannot replace the need to reach “net-zero” emissions of CO2, significant reductions in the methane burden will ease the timescales needed to reach required CO2 reduction targets for any particular future temperature limit. There is no single magic bullet, but implementation of a wide array of mitigation and emission reduction strategies could substantially cut the global methane burden, at a cost that is relatively low compared to the parallel and necessary measures to reduce CO2, and thereby reduce the atmospheric methane burden back toward pathways consistent with the goals of the Paris Agreement

Quantification of potential macroseismic effects of the induced seismicity that might result from hydraulic fracturing for shale gas exploitation in the UK

The furore that has arisen in the UK over induced microseismicity from ‘fracking’ for shale gas development, which has resulted in ground vibrations strong enough to be felt, requires the urgent development of an appropriate regulatory framework. We suggest that the existing regulatory limits applicable to quarry blasting (i.e. peak ground velocities (PGV) in the seismic wavefield incident on any residential property of 10 mm s<sup>−1</sup> during the working day, 2 mm s<sup>−1</sup> at night, and 4.5 mm s<sup>−1</sup>1 at other times) can be readily applied to cover such induced seismicity. Levels of vibration of this order do not constitute a hazard: they are similar in magnitude to the ‘nuisance’ vibrations that may be caused by activities such as walking on wooden floors, or by large vehicles passing on a road outside a building. Using a simple technique based on analysis of the spectra of seismic S-waves, we show that this proposed daytime regulatory limit for PGV is likely to be satisfied directly above the source of a magnitude 3 induced earthquake at a depth of 2.5 km, and illustrate how the proposed limits scale in terms of magnitudes of induced earthquakes at other distances. Previous experience indicates that the length of the fracture networks that are produced by ‘fracking’ cannot exceed 600 m; the development of a fracture network of this size in one single rupture would correspond to an induced earthquake c. magnitude 3.6. Events of that magnitude would result in PGV above our proposed regulatory limit and might be sufficient to cause minor damage to property, such as cracked plaster; we propose that any such rare occurrences could readily be covered by a system of compensation similar to that used over many decades for damage caused by coal mining. However, it is highly unlikely that future ‘fracking’ in the UK would cause even this minor damage, because the amount of ‘force’ applied in ‘fracking’ tends to be strictly limited by operators: this is because there is an inherent disincentive to fracture sterile overburden, especially where this may contain groundwater that could flood-out the underlying gas-producing zones just developed. For the same reason, seismic monitoring of ‘fracking’ is routine; the data that it generates could be used directly to police compliance with any regulatory framework. Although inspired by UK conditions and debates, our proposals might also be useful for other regulatory jurisdictions

STUDY OF THE FORMATION MECHANISM OF GAS HYDRATES OF METHANE IN THE PRESENCE OF SURFACE-ACTIVE SUBSTANCES

Досліджено вплив поверхнево-активних речовин на механізм утворення газових гідратів метану. Визначено значення критичної концентрації міцелоутворення (ККМ) розчинів дібутілфенола, обробленого окисом етилену (ДБ), а також синтанолів (ДС-10, ДС-20). Виявлено, що завдяки процесу солюбілізації відбувається утворення мікрогетерогенних наночасток, які призводять до зміни складу газогідратів і швидкості утворення Ключові слова: газогідрати метану, міцелоутворення, поверхневий натяг, міжфазовий електричний потенціал, швидкість утворенняИсследовано влияние поверхностно-активных веществ на механизм образования газовых гидратов метана. Определены значения критической концентрации мицеллообразования (ККМ) растворов дибутилфенола, обработанного окисью этилена (ДБ), а также синтанолов (ДС-10, ДС-20). Обнаружено, что благодаря процессу солюбилизации происходит образование микрогетерогенных наночастиц, которые приводят к изменению состава газогидратов и скорости образования Ключевые слова: газогидраты метана, мицеллообразование, поверхностное натяжение, межфазный электрический потенциал, скорость образовани

The application of electromagnetic methods for polymetallic prospecting in mining conditions

The paper presents selected results of geophysical surveys carried out in the “Polkowice-Sieroszowice” copper mine in Lower Silesia, Poland. The aim of complex geophysical measurements was the analysis of the usefulness of selected electromagnetic methods for locating ore mineralisation zones in mining conditions. The results were obtained from surveys conducted along profiles designed on the side-wall by the roof, in the middle and the floor of the excavation. Electromagnetic Profiling and Ground Penetrating Radar techniques were applied for outlining the mineralisation zones consisting of Cu, Pb and Fe. The variability of geophysical recordings depending on the degree of mineralisation and distribution of fractures induced by mining activity were analysed. The results of geophysical surveys were correlated to petrophysical parameters and laboratory data concerning the percentages of Cu, Pb and Fe in samples taken from the side-wall at the survey site