Search-Oriented Technique for the Numerical Forecasting of Gold Placers: Evidence from the Vagran Placer District

Aiming at the difficulty of accurately constructing the dynamic model of subtropical high, based on the potential height field time series over 500 hPa layer of T106 numerical forecast products, by using EOF (empirical orthogonal function) temporal-spatial separation technique, the disassembled EOF time coefficients series were regarded as dynamical model variables, and dynamic system retrieval idea as well as genetic algorithm were introduced to make dynamical model parameters optimization search, then, a reasonable non-linear dynamic model of EOF time-coefficients was established. By dynamic model integral and EOF temporal-spatial components assembly, a mid-/long-term forecast of subtropical high was carried out. The experimental results show that the forecast results of dynamic model are superior to that of general numerical model forecast results. A new modeling idea and forecast technique is presented for diagnosing and forecasting such complicated weathers as subtropical high.

A method is presented for analyzing and forecasting the occurrence of lower-atmospheric undular bores over the western and central Gulf of Mexico (GOM) and adjacent land areas using standard operational forecasting and analysis techniques. The method is based on research that has identified a set of sufficient conditions associated with these occurrences realized by observations of the phenomena in recent years and is grounded in the theoretical understanding of undular bores developed during the last century by fluid dynamicists. The approach discusses practical approximations to the theory that allows the operational forecaster to use output from standard numerical and statistical forecast models. In addition to providing an operational method for forecasting the time and location of occurrence, the technique provides a methodology for analyzing and anticipating the strength, forward speed, and horizontal wavelength of the phenomena.

This article describes recent advances in the techniques of weather forecasting, notably the automation of observing methods, the production of objective numerical forecasts with the aid of powerful computers and the use of cloud pictures and other data from satellites. The high quality of the computed charts and the promising results of research on even more complex mathematical models of the atmosphere strongly suggest that, given an adequate global coverage of observations, faster communications and much more powerful computers than exist at present, it will be possible to produce more accurate forecasts that will remain reliable for 5-7 days ahead. These global requirements are being planned as a major objective of the World Weather Watch but they cannot be adequately met by expansion of the present operational system. Continuous global surveillance of the atmosphere will be possible only from satellites which, besides observing the cloud cover, can also be expected to determine the distribution of temperature, pressure, humidity, etc., by sensing the atmosphere's emitted radiation, and to measure winds by tracking drifting balloons. Satellites are also likely to be used for interrogating unmanned weather stations on land, ships, ocean buoys and balloons, and for relaying the data to ground stations for processing and analysis by computer. Promising techniques for achieving these aims are described and assessed in the second part of the article.

The oldest mines in the United States are in north-central New Mexico. Turquoise was mined before 900 A.D., lead and silver before 1600, and gold after 1828. Mining for base metals and coal began in 1880 but is now negligible. Since 1945, industrial nonmetals have been produced near Albuquerque.The Cerrillos (turquoise, lead, zinc, silver, copper), Old Placer (gold, tungsten), and New Placer (gold, copper, lead, zinc, silver, tungsten) districts are in a belt of early Tertiary monzonite stocks and laccoliths. Production from placers, breccia pipes, pyrometasomatic deposits, limestone replacement pipes, and veins has totaled about $11 million. "Red beds" copper deposits (Nacimiento district) and epithermal gold-silver veins (Cochiti district) have each yielded more than $1 million.Quaternary sediments of the Rio Grande provide sand and gravel. Brick and tile are made from Pennsylvanian and Cretaceous shales and building blocks of pumice and scoria from Quaternary volcanoes. A cement plant and two gypsum products plants, opened in 1959 and 1960, use limestone, dolomite, and shale from the Madera Formation (Pennsylvanian), gypsum from the Todilto Formation (Jurassic), and natural gas from the San Juan Basin. Annual production of nonmetals ranges from $9 to $13 million. Deposits of silica sand, bentonite, fluorspar, barite, marble, sulfur, perlite, and ocher are known but not currently (1966) worked.Near Cerrillos, 7 million tons of coking bituminous coal and anthracite have been mined; thermal metamorphism accounts for the rank. Elsewhere, bituminous coal occurs in folded and faulted coal beds of intermontane basins and subbituminous coal in flat-lying beds of the Colorado Plateau. The coals are Upper Cretaceous (Mesaverde and Fruitland formations). Reserves are estimated at 5 billion tons, including 53 million tons near Cerrillos. Although oil and gas production of the three-county area is not large, proximity to the San Juan gas field is a favorable economic factor.

MaCOM model takes the international advanced numerical model NEMO as the power core, coupled with the sea ice model, with the horizontal grid resolution better than 10 km and a total of 75 layers in vertical direction. On this basis, a comprehensive integrated numerical forecasting system with data collection system as the root, ensemble assimilation system as the backbone, forecasting system as the branch and product production system as the terminal has been developed, forming a distributed and loosely coupled tree operation and maintenance architecture with four subsystems: data collection, data assimilation, numerical forecasting and product distribution.In order to test the MaCOM model forecasting effect, the MaCOM model is used to make day-by-day forecasts of temperature, salt, current, sea surface height and other variables of the global ocean for the whole year of 2020. This experiment focuses on evaluating the model performance, and to avoid differences in assimilation systems, the global 1/12 resolution day-by-day analysis field of the PSY4 model v3r1 version of the Mercator Center in France is selected as the initial field of the model; the GFS meteorological forecast field data is used as the model upper surface forcing field to drive the model; the model is run from the forecast moment with a forecast time limit of 7 days, and after each forecast process the The forecast results are interpolated to the standard latitude and longitude grid and depth after each forecast process; other settings of the model remain unchanged.The model forecasts are compared using the GOV IV-TT (The GODAE Oceanview Intercomparison and Validation Task Team) Class 4 standard method, which is commonly used to evaluate the performance of forecast systems and forecast skill. The statistics used in the evaluation are based on the comparison of model forecasts with observations, including root mean square error (RMES), bias (Bias), and anomaly correlation, as well as comparing forecasts with climatology and persistence.The following conclusions were obtained from the 2020  evaluation:The MaCOM model sea surface temperature forecasts are less biased and closer to the live observations, with RMSE around 0.6℃ and better forecast stability, and PSS and CSS show that the model has obvious positive skill. The vertical structure test of the MaCOM model shows that the RMSE is around 0.6℃, and the forecastability of temperature profiles in the Southern Ocean, Indian Ocean, South Pacific, North Pacific and other Southern Hemisphere regions is better than that of the PSY4 model. The RMSE of sea surface height anomaly of MaCOM model is around 0.05m, which is smaller than that of PSY4. The PSS test indicates that the forecasting skill of MaCOM model for sea surface height anomaly needs further improvement. MaCOM has better forecasts than PSY4 for sea surface temperature, vertical structure of temperature and salt, and sea surface height anomalies; among them, it has effective forecasting techniques for vertical structure of temperature and salt and sea surface temperature, and can better simulate the weather-scale variability, which has good operational application value.

Authigenic gold in placers of the Amylo-Sistigkhemsky ore placer district of the Khemchik-Kurtushubinsky metallogenic zone of the Western Sayan has been studied by electron microscopic method. Structural-morphological features and chemical composition of natural and anthropogenic varieties of new (authigenic) gold of repeatedly developed placers are revealed and systematized in the present work. Aggregates of authigenic gold are represented by rims, flakes, cryptoconical and hair-like outgrowths of chemogenic-biogenic natural authigenic silver gold (937–1,000 ‰), polyphase rims of technogenic goldsilver amalgam (Au 71–95,2 %; Ag n/o– 4.3 %; Hg 4.75–25 %) and entangled-fiber aggregates of technogenic-biogenic mercury gold (Au 71.1–81.5 %; Ag 2.75–5.9 %; Hg 15.2–23.4 %). Electrochemical methods of deposition and sorption of gold and mercury by cyanobacteria cells played the predominant role in the formation of authigenic gold and iron hydroxide layers. The mass amount of authigenic gold is less than tenths of %. The formation of authigenic gold occurs at the stage of syngenesis, during the formation of natural gold-bearing strata and during the formation of gold-bearing separated payers in anthropogenic dumps broken by a significant time interval. Authigenic gold deposition occurs from pore waters saturating the sediment of terrigenous material, to a greater extent, in the upper zone of the gold-bearing layer. Gold in pore waters is in the form of Au ions, colloids and complex compounds of AuClOH–, and AuCl(OH)2 – ; AuCl2– ; (Au,Ag)(S2O3)3– and others. Gold deposition was carried out by chemogenic method; largely the formation of aggregates of authigenic gold was promoted by goldophilic bacteria. Galvanic processes played a significant role in the caogulation of gold-bearing colloids and recovery of gold from weakly saturated true solutions. In our opinion, the formation of high-grade rims due to metasomatic purification of metal from Ag and Cu impurities caused the formation of positive charge on the surface of clastogenic gold particles. Layers of iron hydroxides and new gold were deposited on the positively charged surface as a result of galvanic process from pore waters.

Residual-eluvial gold placers in northeastern Russia (Dal’nii placer)

This study seeks to demystify the claim that the ‘atmospheric chaos’ imposes a two-week limit on reliable weather forecasts. ‘Deterministic chaos’ indeed occurs due to the use of nonlinear numerical models for these forecasts. This ‘deterministic chaos’ does impose time limits on valid predictions, but it also facilitates, through the ensemble forecasting technique, the use of interesting statistical indicators that define regions and the duration these predictions are more or less reliable. Recently published articles show that the ‘uncertainties’ in the initial conditions are an inherent difficulty in meteorological observations and have nothing to do with the atmospheric behavior. These studies demonstrate two important aspects regarding ‘uncertainties’ in data used to initialize models. First, to achieve improvements in numerical weather forecasts, these ‘uncertainties’ must be skillfully introduced in the large scale and not in the small scale. Secondly, the numerical models must include equations or parameterizations that reproduce nature’s ways that let different scales ‘interact’, that is, the models should reproduce how the energy of different atmospheric modes ‘travels’.

Gold lodes and placers of the Willow Creek District. Mineral resources of the upper Matanuska and Nelchina valleys. Preliminary report on the Broad Pass region. Mining in the Valdez Creek placer district

Climate warming is causing an increase in the total moisture content on the planet and in the number of heavy rainfall cases. Many of these result in severe flooding, victims, and destruction of infrastructure. The aim of the study is to establish the possibility of improving the quality of heavy precipitation forecasting by reducing the step of the computational grid in the mathematical model of the atmosphere. The article presents the results of a study of extreme summer precipitation in the Ural Kama region for the period from 1979 to 2015. The statistical characteristics of 37 precipitation cases with an intensity of more than 50 mm in 12 hours were analyzed. Computational experiments were performed on the WRF-ARW regional atmospheric model. The meteorological conditions for the occurrence of heavy rain in town of Gubakha with an extreme intensity of 114,5 mm in 12 hours were taken as a special case for the study. A qualitative assessment of the simulation results showed that for the selected case, the model correctly reproduced the general structure of heavy rains, but significantly shifted it eastward. A quantitative assessment of the forecast quality was conducted for numerical forecast of heavy precipitation based on the WRF-ARW model at a grid step of 3 km and 7,2 km. The quality of the model was evaluated based on the forecast accuracy not only at the measurement point but also in the vicinity within a radius of 50 km. It was found that there was no significant improvement in the quality of the forecast of high-intensity precipitation when switching to a smaller grid step according to both the first and second assessment methods. The results obtained can be taken into account when preparing forecasts of heavy rains occurrence and when developing flood forecast techniques.

Potential for lode deposits in the Livengood gold placer district, east-central Alaska

The Nansen-Big Creek placer district has been a centre of placer mining and prospecting in Dawson Range since the tum-of-the century. Placers occur in this region due to a Jack of glaciation for more than 1 Ma and the presence of late Cretaceous granites and the subvolcanic Mount Nansen Group which are gold sources or induced mineralization in country rocks. Placers were created during stream degradation following the pre-Reid glaciations. Significant aggradation occurred along streams in the Dawson Range as a result of the Reid Glaciation. The subsequent McConnell Glaciation had a minimal affect on them by comparison. Ali streams that cross or drain late Cretaceous granites and the Mount Nansen Group and are beyond the limits of Reid Glaciation are prospective for gold placers.

The geology of Arctic Canada is divided into the cratons or granitic and metamorphic roots of the Canadian shield which contain much of the gold, copper, nickel, iron, uranium, rare earth elements and diamond deposits. The bounding Mesoproterozoic to Phanerozoic platforms, basins and accreted terrains of the Interior platform and Canadian Cordillera, which extend into the High Arctic, contain much of the zinc, lead, gold, silver, copper, molybdenum and tungsten resources. Basement nuclei in the Canadian shield are the four Archean cratons. Oldest of these is the Slave craton (4030-2550 Ma) on the west side of the shield. It is bound by Paleoproterozoic orogens: Thelon-Taltson to the east, Wopmay to the west and the Athapuskow aulcogen to the south in the east arm of Great Slave Lake. The Slave craton is associated with orogenic gold, volcanogenic massive sulphides (VMS), diamond-rich kimberlites and a large REE deposit. Lying to the east and underlying most of the remaining parts of the Canadian shield across the Canadian Arctic are the Rae (3250-2580 Ma) and Hearne (2740-2540 Ma) cratons. Significant in the Meso- to Neoarchean Rae craton are supracrustal rocks containing important resources of iron, orogenic gold of Paleoproterozoic age, uranium associated with a sub- Paleoproterozoic unconformity, nickel and commercially significant diamond-rich kimberlites. Known resoources in the Hearne craton include nickel, copper, platinum group elements (PGE), uranium and VMS. The fourth craton is represented by the Superior craton, mostly located south of latitude 60 but also exposed in the northern extremity of Quebec. It is bound to the north by the Paleoproterozoic Cape Smith belt (1870-1800 Ma), part of the circum-Superior Trans-Hudson orogen. This belt is noted for its important resources of nickel, copper and platinum group elements. The other significant Paleoproterozoic belt is represented by the Wopmay orogen (1890-1840 Ma) which lies west of the Slave Craton. This features an eastern sedimentary belt and, to the west, the plutonic and volcanic rocks of the Great Bear magmatic zone. Noteworthy resources include iron oxide-copper-gold (IOCG), polymetallic veins and vein uranium. The Precambrian cratons and Paleoproterozoic basins are fringed to north and west by Mesoproterozoic to upper Paleozoic shelf carbonate sequences. These rocks contain carbonate-hosted (MVT) zinc-lead deposits. Also present in this realm are iron deposits, notably the very large Crest deposit in Neoproterozoic strata. Southwestward the shelf succession gives way to Cambrian to Devonian deep water sediments of the Selwyn Basin. Important resources within the Selwyn Basin include three shale-hosted zinc-lead deposits in the Yukon and two significant VMS copper-zinc deposits. The western part of the Yukon is dominated by Jurassic and Cretaceous accreted terranes and associated granitoid rocks. This is a key realm for gold, polymetallic silver-lead-zinc veins and nickel-copper-PGE. Also associated with Mesozoic intrusives are tungsten and copper skarns, and copper-molybdenum porphyry deposits. Rounding out the resources of the Yukon are eleven gold placer districts of which the Klondike is most significant.

Structural Conditions of the Bedrock Noble Metal Mineralization in the Kherpuchi–Vayun Gold Placer District (Khabarovsk Region)

The Porcupine gold placer district, Alaska