Self‐potentials associated with the Yanacocha high‐sulfidation gold deposit in Peru

Geophysics ◽  
2002 ◽  
Vol 67 (3) ◽  
pp. 684-689 ◽  
Author(s):  
Mark Goldie
Keyword(s):  
Apparent Resistivity ◽  
Direct Relationship ◽  
Field Measurements ◽  
Gold Deposits ◽  
Mineral Deposits ◽  
Silica Body ◽  
High Sulfidation ◽  
Extensive Field ◽  
Self Potential ◽  
Peak Value

Significant self‐potential (SP) anomalies characterize the large silica bodies associated with high‐sulfidation oxide gold deposits in the Yanacocha district, Peru. Large SP effects and high apparent resistivities have been observed that coincide with areas of intense silicification. Negative SP anomalies of several volts have been routinely recorded on numerous projects and deposits. The peak value measured was −10.2 V. A direct relationship is shown to exist between the magnitude of an SP response and the size and apparent resistivity of a silica body. Extensive field measurements over numerous high‐sulfidation deposits show that the negative SP effect increases with the size and/or resistivity contrast associated with these unique mineral deposits.

scholarly journals Measurement of unsaturated meltwater percolation flux in seasonal snowpack using self-potential

2021 ◽  
pp. 1-16
Author(s):  
Wilson S. Clayton
Keyword(s):  
Method Development ◽  
Water Saturation ◽  
Field Measurements ◽  
Time Domain Reflectometry ◽  
Electrode Spacing ◽  
Glacier Mass Balance ◽  
Wetting Front ◽  
Electrical Field Strength ◽  
Water Redistribution ◽  
Self Potential

Abstract This paper presents a feasibility study of in situ field measurements of unsaturated meltwater percolation flux within the vertical profile of a snowpack, using the self-potential (SP) method. On-site snowmelt column tests calibrated the SP measurements. The SP data measured electrical field strength with an electrode spacing of 20 cm, and coincident water saturation (Sw) measurements using time domain reflectometry allowed calculation of SP-modeled vertical percolation flux (qsp), expressed as Darcy velocity. The results reflected transient diurnal snowmelt dynamics, with peak flux lagging arrival of a saturation wetting front. Peak daily qsp was 60 to >300 mm d−1, whereas daily snowmelt was 20–50 mm w.e. Surface refreezing events appeared to cause upward flow, possibly representing water redistribution toward the freezing boundary. Calculated fluxes were comparable to actual fluxes, although average errors ranged from −15 to +46% compared to average of melt expected from surface energy-balance and ablation stake measurements. By advancing method development to measure unsaturated meltwater percolation flux in snowpacks this study creates opportunities to study fundamental snowmelt processes, may improve mathematical modeling and may supplement glacier mass-balance studies and studies of snowmelt interactions with avalanches, groundwater and surface water.

Valuation of growing stock using multisource GIS data, a stem quality database, and bucking simulation

2018 ◽  
Vol 48 (8) ◽  
pp. 888-897 ◽  
Author(s):  
Blanca Sanz ◽  
Jukka Malinen ◽  
Vesa Leppänen ◽  
Rubén Valbuena ◽  
Tuomo Kauranne ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Field Measurements ◽  
Product Yield ◽  
Optimization Methods ◽  
Raw Material ◽  
Diameter Distribution ◽  
Target Area ◽  
Product Price ◽  
Extensive Field ◽  
Stem Quality

Customer-oriented production as a sawmill strategy requires up-to-date information on the available raw material resources. Bucking is a process in which the tree stem is divided into products based on the roundwood user’s needs regarding products and their quality and dimensions. Optimization methods are employed in bucking to recover the highest value of the stem for a given product price matrix and requested length–diameter distribution. A method is presented here for assessing the value of harvestable timber stands based on their product yield. Airborne laser scanning, multispectral imagery, and field plots were used to produce timber statistics for a grid covering the target area. The statistics for the plots were generated from this grid. The value of the estimated tree list was assessed using a bucking-to-value simulator together with a stem quality database. Different product yield simulations in terms of volumes, timber assortment recoveries, wood paying capabilities (WPC) and value estimations based on the presented method, and extensive field measurements were compared. As a conclusion, this method can estimate WPC for pulpwood and sawlogs with root mean squared errors of 32.7% and 38.5%, respectively, relative to extensive field measurements.

Multistage Thrust and Nappe Tectonics in the Southeastern Part of East Sayan and Its Role in the Formation of Large Gold Deposits

2021 ◽  
Vol 62 (1) ◽  
pp. 109-120 ◽  
Author(s):  
I.V. Gordienko ◽  
N.L. Dobretsov ◽  
S.M. Zhmodik ◽  
P.A. Roshchektaev
Keyword(s):  
Volcanic Eruptions ◽  
Gold Deposits ◽  
Mineral Deposits ◽  
Early Paleozoic ◽  
Late Cenozoic ◽  
Paleoasian Ocean ◽  
Southeastern Part ◽  
Nappe Tectonics ◽  
Sayan Region ◽  
Igneous Complexes

Abstract ––Comprehensive studies of structural geology and metallogeny, taking into account the authors’ previous works started as early as the last century, have shown that the southeastern part of East Sayan formed mainly in the Neoproterozoic–early Paleozoic in the settings of multistage thrust and nappe tectonics and tectonomagmatic restructuring of autochthonous and overthrust allochthonous oceanic (ophiolitic), island arc, and ocean-marginal terranes as well as amalgamation of accretion–collision and postcollisional igneous complexes that formed during the opening and subsequent closure of the Paleoasian Ocean marginal structures. In the middle and late Paleozoic, active intraplate volcanic and plutonic processes continued in the thrust/overthrust fault setting, which led to the formation of new dome-shaped nappe structures and the redistribution of ore matter (gold etc.) in large mineral deposits. The final structure of the East Sayan region formed during the late Cenozoic as a result of mountain uplifting and volcanic eruptions, including those in the valley of the Zhombolok River.

Mineral Deposits of Myanmar (Burma)

10.5382/gb.62 ◽  
2021 ◽  
Author(s):  
Laurence Robb ◽  
Andrew Mitchell
Keyword(s):  
Massive Sulfide ◽  
Gold Deposits ◽  
Late Triassic ◽  
Mineral Deposits ◽  
Magmatic Arc ◽  
Silver Deposits ◽  
Copper Gold ◽  
Lead Zinc ◽  
Lead Nickel ◽  
Complex Geology

Myanmar is richly endowed in natural resources that include tin, tungsten, copper, gold, zinc, lead, nickel, and silver, as well as gemstones. The material covered over a nine-day field trip explores the country’s complex geology, which reflects a collisional history stretching from the Late Triassic to at least Miocene, sited at the eastern end of the India-Asia suture. The country can be divided into three principal metallotects: the Wuntho-Popa magmatic arc, with granites and associated porphyry-type and epithermal Cu-Au mineralization; the Slate Belt (also called the Mogok-Mandalay-Mergui Belt), with multiple precollisional I-type and postcollisional S-type crustal melt granites that host significant tin-tungsten mineralization, and which also are host to a number of orogenic gold deposits; and the Shan Plateau with massive sulfide-type and also MVT-style lead-zinc-silver deposits.

Irkutsk school of mining engineers is celebrating 90th anniversary

2021 ◽  
Vol 44 (4) ◽  
pp. 358-368
Author(s):  
B. L. Talgamer
Keyword(s):  
Underground Mining ◽  
Mining Industry ◽  
Gold Deposits ◽  
Educational Process ◽  
Open Pit ◽  
Mineral Deposits ◽  
Mining Institute ◽  
Mining Operations ◽  
Design Work ◽  
Research And Design

It is in 1930 that the training of mining engineers began in Eastern Siberia on the basis of the Siberian Mining Institute (now Irkutsk National Research Technical University). In 1931 the Department of Mining Arts was organized, which later was named the Department of Mineral Deposits Development. Over the years, the Department has trained more than 7000 graduates – mining engineers, who made a huge contribution in the development of the mining industry in the Irkutsk region and neighboring territories including Mongolia. The Department has trained more than a hundred mining engineers and Masters of science for Mongolia; assisted the lecturers and professors of the Mongolian Polytechnic University (now Mongolian University of Science and Technology) in organizing the educational process for training specialists for the country's mining industry. At its different formation stages the Department of Mineral Deposits Development was headed by well-known scientists – mining engineers, who created three scientific schools for the development of coal, placer and gold deposits; the obtained scientific results were marked with two State awards of the Russian Federation, dozens of doctoral and candidate dissertations were defended and about 100 patents were received. Today, the Department super- vises the training of mining engineers in open-pit and underground mining of mineral deposits, carries out a large amount of research and design work on the orders from mining enterprises, trains academic staff, develops new technologies and technical solutions in order to improve mining operations. The Department is deeply involved in the cooperation with mining enterprises, research and design organizations, as well as with universities that train mining engineers.

Evaluation of Electrical Resistivity for Non-destructive Seepage Detection on an Urban Underground Diaphragm Wall

2020 ◽  
Vol 25 (1) ◽  
pp. 1-14
Author(s):  
Cai Yang ◽  
Shengdong Liu ◽  
Enjie Ding ◽  
Haiping Yang ◽  
Jingyan Xie
Keyword(s):  
Electrical Resistivity ◽  
Apparent Resistivity ◽  
Diaphragm Wall ◽  
Coupled Analysis ◽  
Leakage Detection ◽  
Response Characteristics ◽  
Before And After ◽  
Potential Methods ◽  
Self Potential ◽  
Non Destructive

With the continuous development of urban underground space, non-destructive methods for diaphragm wall leakage detection are becoming increasingly important. Recent studies have shown that the apparent resistivity, stimulated current, and self-potential can be used as indicator parameters for non-destructive diaphragm wall leak detection. The diaphragm wall seepage evaluation of a subway station was carried out using the above indicator parameters. The response characteristics of apparent resistivity, stimulated current, and self-potential were obtained before and after excavating the diaphragm wall. The results obtained by this study reveal that an area is very likely to be a seepage area when there are significant differences amongst the three measurement parameters. The self-potential is greatly affected by field interference; the stimulated current is a direct sign of seepage, and indicates that seepage occurs when the stimulated current increases; the apparent resistivity macroscopically indicates rupture or seepage in the diaphragm wall. The field experiment verified the feasibility of detecting diaphragm wall seepage using coupled analysis based on electrical resistivity and self-potential methods.

scholarly journals Outburst flood hazard for glacier-dammed Lac de Rochemelon, France

2010 ◽  
Vol 56 (195) ◽  
pp. 91-100 ◽  
Author(s):  
C. Vincent ◽  
S. Auclair ◽  
E. Le Meur
Keyword(s):  
Flood Hazard ◽  
High Sensitivity ◽  
Field Measurements ◽  
Drainage Channel ◽  
Temperature Model ◽  
Outburst Flood ◽  
Good Opportunity ◽  
Available Energy ◽  
Extensive Field ◽  
Energy Dissipated

AbstractSupraglacial Lac de Rochemelon was formed 50 years ago behind an ice dam and grew steadily until 2004. In October 2004, the volume of the lake reached 650 000 m3, bringing its surface within 0.2 m of the top of the ice dam. To eliminate the threat to towns located below in the event of an overflow, the lake was drained artificially in October 2004 and during the summer of 2005. Once the volume had been reduced to 250 000 m3 by siphoning, a channel was dug with explosives and the remaining water overflowed naturally. This offered a very good opportunity to investigate the breaching of an ice dam accompanied by thermal erosion of the drainage channel. Extensive field measurements were carried out during drainage. Analysis of the energy dissipated in the channel reveals that only half of the available energy was used for breach erosion. A numerical model was used to simulate the evolution of a number of variables during drainage and to study the sensitivity of discharge and ice erosion to different parameters, revealing a high sensitivity to water temperature. Model simulations indicate that natural drainage of this lake at the beginning of October 2004 would have led to a peak discharge of <6 m3 s−1.

scholarly journals Comparative Analysis of SAR and Temperature Rise within Head Tissues Exposed to Radiofrequency Radiation From GSM Transceiver Base Station in South-South Nigeria.

2017 ◽  
Vol 13 (4) ◽  
pp. 4956-4961
Author(s):  
Ushie Patrick ◽  
O.D. Osahon ◽  
O. A. Ojo
Keyword(s):  
Temperature Rise ◽  
Near Field ◽  
Field Measurements ◽  
Threshold Value ◽  
Base Station ◽  
Whole Body ◽  
Threshold Values ◽  
Worst Case ◽  
Base Station Antennas ◽  
Peak Value

In this study, measurement of radiofrequency exposure due to cellular transceiver base station antennas was carried out. Both far and near field measurements of electric field and magnetic field level were made around selected transceiver base station antennas in selected South-South States Nigeria, with the aid of frequency-dependent equipment (CORNET, Electrosmog meter ED78S EMF RF/LF Dual mode model). The results obtained were analysed using thermal related indices such as specific absorption rate (SAR) with peak value in cerebrospinal fluid-CSF (0.095358W/kg), temperature rise with peak also in CSF (0.008381 oC). These results were compared with threshold values of 2 W/kg and 0.08 W/kg for SAR (over the head and whole body respectively), and 1oC for temperature rise as set by International Commission of Non Ionizing Radiation Protection (ICNIRP). The results indicate that none of the network operators in the study area have SAR above the recommended threshold value with the worst case observed in Calabar. 

scholarly journals Geomechanical conditions of vein gold deposits in permafrost zone

2020 ◽  
Vol 192 ◽  
pp. 01026
Author(s):  
Arkady Avdeev ◽  
Elena Sosnovskaya
Keyword(s):  
Field Measurements ◽  
Gold Deposits ◽  
Permafrost Zone ◽  
Initial Stresses ◽  
Qualitative Assessment ◽  
Electric Transport ◽  
Mining Operations ◽  
Initial Development ◽  
Temperature Conditions ◽  
Vein Deposits

Developing the vein deposits in the permafrost zone results in specific geomechanical conditions. The paper describes the main results of studies of the geomechanical conditions of 8 vein deposits located in the permafrost zone for 2000-2020. In the process of research, zoning of the temperature conditions in mines has been carried out. The research has established the position of the permafrost zones, the natural transition zones of frozen rocks to thawed rocks, the zones of seasonal ventilation thawing and technogenic thawing. The authors have made the qualitative assessment of the degree of stability of the mine workings and pillars, taking into account the temperature conditions. It is proposed, when evaluating the stability of structural elements of geotechnologies, to adjust the strength properties of rocks using a differentiated coefficient of structural weakening. The paper has presented the results of field measurements of the initial stress-deformed state at various temperature conditions. The general regularities of the distribution of initial stresses are established: hydrostatic stresses act in frozen rocks, and increased gravitational-tectonic stresses act in natural and technogenic thawed rocks. The authors have proposed to use the obtained results as boundary conditions for the calculation of geotechnological parameters in the design and initial development of vein gold deposits of the permafrost zone. The authors have proposed the measures to improve the safety of mining operations in permafrost: thermal insulation of mine walls, use of electric transport, regulation of ventilation.

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