Study of change in the leaching solution activity after treatment with a cavitator

Purpose. Increasing the valuable component content in a pregnant solution due to the activation of leaching solution with cavitation treatment in case of the borehole in-situ leaching (ISL). Methods. To obtain the cavitation effect, a laboratory cavitation plant has been produced. Studies on the sulphuric acid solution activation by means of cavitation were conducted using solutions with 10 g/l of acid content. Studies of changing the sulphuric acid solution activity during treatment with a cavitator were conducted for 3 minutes (24 passes through the cavitator), 5 minutes (40 passes), 10 minutes (80 passes) and 20 minutes (160 passes). The content in the solution of the valuable component was analysed using a KFK-3-“ZOMS” photoelectric photometer. Findings. The laboratory studies have been performed to set the influence of the cavitation process on the leaching solution activity at various degrees of activation and time of reaction. The studies have established that in order to activate the leaching solution, it is proposed to carry out cavitation treatment of sulphuric acid before to additionally fortify the mother solution, which helps to increase its activity. The solution activation leads to an increase in the valuable component content from 18 to 26% in the pregnant solution and its activity is maintained for a long time (up to 30 days). Originality. New dependences have been obtained reflecting the nature of changing the valuable component content in the pregnant solution on the reaction time and the degree of solution activation. Practical implications. The proposed activation method leads to an increase in the valuable component content in the pregnant solution compared to the basic technology, therewith, the activity is maintained for a long time. The proposed technology is characterized by low capital costs, is easily integrated into the existing system and is absolutely environmentally friendly.Мета. Підвищення вмісту корисного компоненту в продуктивному розчині за рахунок активації вилуговуючого розчину кавітаційною обробкою при підземному свердловинному вилуговуванні. Методика. Для отримання ефекту кавітації була виготовлена лабораторна кавітаційна установка. Дослідження з активації сірчанокислотного розчину кавітацією проведені на розчинах з вмістом кислоти 10 г/л. Дослідження зміни активності сірчанокислотного розчину при обробці кавітатором проводили протягом 3 хвилин (24 проходи через кавітатор), 5 хвилин (40 проходів), 10 хвилин (80 проходів) і 20 хвилин (160 проходів). Аналіз вмісту корисного компонентау в розчині вели з використанням фотоелектричного фотометра КФК-3-“ЗОМС”. Результати. Виконані лабораторні дослідження зі встановлення впливу процесу кавітації на активність вилуговуючого розчину при різному ступені активації та часу реакції. Дослідженнями встановлено, що для активації вилуговуючого розчину пропонується проводити кавітаційну обробку сірчаної кислоти перед дозміцненням маточного розчину, що сприятиме підвищенню її активності. Активація розчину призводить до збільшення вмісту корисного компоненту в продуктивному розчині від 18 до 26% і її активність зберігається протягом тривалого часу (до 30 днів). Наукова новизна. Отримано нові залежності, що відображають характер зміни вмісту корисного компоненту в продуктивному розчині від часу реакції та ступеня активації розчину. Практична значимість. Запропонований спосіб активації призводить до збільшення вмісту корисного компоненту в продуктивному розчині у порівнянні з базовою технологією, при цьому активність зберігається протягом тривалого часу. Запропонована технологія відрізняється низькими капітальними витратами, легко інтегрується в існуючу систему й екологічно абсолютно безпечна.Цель. Повышение содержания полезного компонента в продуктивном растворе за счет активации выщелачивающего раствора кавитационной обработкой при подземном скважинном выщелачивании. Методика. Для получения эффекта кавитации была изготовлена лабораторная кавитационная установка. Исследования по активации сернокислотного раствора кавитацией проведены на растворах с содержанием кислоты 10 г/л. Исследования изменения активности сернокислотного раствора при обработке кавитатором проводили в течение 3 минут (24 прохода через кавитатор), 5 минут (40 проходов), 10 минут (80 проходов) и 20 минут (160 проходов). Анализ содержания полезного компонента в растворе вели с использованием фотоэлектрического фотометра КФК-3-“ЗОМС”. Результаты. Выполнены лабораторные исследования по установлению влияния процесса кавитации на активность выщелачивающего раствора при различной степени активации и времени реакции. Исследованиями установлено, что для активации выщелачивающего раствора предлагается проводить кавитационную обработку серной кислоты перед доукреплением маточного раствора, что способствует повышению ее активности. Активация раствора приводит к увеличению содержания полезного компонента в продуктивном растворе от 18 до 26% и ее активность сохраняется длительное время (до 30 дней). Научная новизна. Получены новые зависимости, отражающие характер изменения содержания полезного компонента в продуктивном растворе от времени реакции и степени активации раствора. Практическая значимость. Предложенный способ активации приводит к увеличению содержания полезного компонента в продуктивном растворе по сравнению с базовой технологией, при этом активность сохраняется длительное время. Предлагаемая технология отличается низкими капитальными затратами, легко интегрируется в существующую систему и экологически абсолютно безопасна.This research was conducted as part of the business contract implementation with JV “Akbastau”, No. 281/ Akb-16 of 23 December, 2016 and as part of the research-development work “Development of technology for mining and extraction of gold from poor ore veins”, performed within the framework of the program “Mo-dernization of technologies and production in the mining and mining-processing industries of the republic of Kazakhstan”, No. 266 of 28 March, 2018. The authors express their gratitude to Doctor of Technical Sciences, Professor H.A. Yusupov, Professor G.G. Kurapov and to Chief Research Scientist S.A. Yusupov for assistance and valuable advice in conducting this research

Fluid pressure heterogeneity during fluid flow in rocks: New laboratory measurement device and method

We present a new type of transducer capable of measuring local pore fluid pressure in jacketed rock samples under elevated confining pressure conditions. The transducers are passive (strain-gauge based), of small size (7 mm in diameter at the contact with the rock and around 10 mm in length), and have minimal dead volume (a few mm3). The transducers measure the differential pressure between the confining fluid and the internal pore pressure. The design is easily adaptable to tune the sensitivity and working pressure range up to several hundred megapascals. An array of four such transducers was tested during hydrostatic pressurization cycles on Darley Dale sandstone and Westerly granite. The prototypes show very good linearity up to 80 MPa with maximum deviations of the order of 0.25 MPa, regardless of the combination of pore and confining pressure. Multiple internal pore pressure measurements allow us to quantify the local decrease in permeability associated with faulting in Darley Dale sandstone, and also prove useful in tracking the development of pore pressure fronts during transient flow in low permeability Westerly granite

Dilatancy stabilises shear failure in rock

Failure and fault slip in crystalline rocks is associated with dilation. When pore fluids are present and drainage is insufficient, dilation leads to pore pressure drops, which in turn lead to strengthening of the material. We conducted laboratory rock fracture experiments with direct in-situ fluid pressure measurements which demonstrate that dynamic rupture propagation and fault slip can be stabilised (i.e., become quasi-static) by such a dilatancy strengthening effect. We also observe that, for the same effective pressures but lower pore fluid pressures, the stabilisation process may be arrested when the pore fluid pressure approaches zero and vaporises, resulting in dynamic shear failure. In case of a stable rupture, we witness continued prolonged slip after the main failure event that is the result of pore pressure recharge of the fault zone. All our observations are quantitatively explained by a spring-slider model combining slip-weakening behaviour, slip-induced dilation, and pore fluid diffusion. Using our data in an inverse problem, we estimate the key parameters controlling rupture stabilisation, fault dilation rate and fault zone storage. These estimates are used to make predictions for the pore pressure drop associated with faulting, and where in the crust we may expect dilatancy stabilisation or vaporisation during earthquakes. For intact rock and well consolidated faults, we expect strong dilatancy strengthening between 4 and 6 km depth regardless of ambient pore pressure, and at greater depths when the ambient pore pressure approaches lithostatic pressure. In the uppermost part of the crust (<4 km), we predict vaporisation of pore fluids that limits dilatancy strengthening. The depth estimates where dilatant stabilisation is most likely coincide with geothermal energy reservoirs in crystalline rock (typically between 2 and 5 km depth) and in regions where slow slip events are observed (pore pressure that approaches lithostatic pressure)

Heterofusion: Fusing genomics data of different measurement scales

In systems biology, it is becoming increasingly common to measure biochemical entities at different levels of the same biological system. Hence, data fusion problems are abundant in the life sciences. With the availability of a multitude of measuring techniques, one of the central problems is the heterogeneity of the data. In this paper, we discuss a specific form of heterogeneity, namely, that of measurements obtained at different measurement scales, such as binary, ordinal, interval, and ratio-scaled variables. Three generic fusion approaches are presented of which two are new to the systems biology community. The methods are presented, put in context, and illustrated with a real-life genomics example

The importance of transport model uncertainties for the estimation of CO2 sources and sinks using satellite measurements

This study presents a synthetic model intercomparison to investigate the importance of transport model errors for estimating the sources and sinks of CO2 using satellite measurements. The experiments were designed for testing the potential performance of the proposed CO2 lidar A-SCOPE, but also apply to other space borne missions that monitor total column CO2. The participating transport models IFS, LMDZ, TM3, and TM5 were run in forward and inverse mode using common a priori CO2 fluxes and initial concentrations. Forward simulations of column averaged CO2 (xCO2) mixing ratios vary between the models by s=0.5 ppm over the continents and s=0.27 ppm over the oceans. Despite the fact that the models agree on average on the sub-ppm level, these modest differences nevertheless lead to significant discrepancies in the inverted fluxes of 0.1 PgC/yr per 106 km2 over land and 0.03 PgC/yr per 106 km2 over the ocean. These transport model induced flux uncertainties exceed the target requirement that was formulated for the A-SCOPE mission of 0.02 PgC/yr per 106 km2, and could also limit the overall performance of other CO2 missions such as GOSAT. A variable, but overall encouraging agreement is found in comparison with FTS measurements at Park Falls, Darwin, Spitsbergen, and Bremen, although systematic differences are found exceeding the 0.5 ppm level. Because of this, our estimate of the impact of transport model uncerainty is likely to be conservative. It is concluded that to make use of the remote sensing technique for quantifying the sources and sinks of CO2 not only requires highly accurate satellite instruments, but also puts stringent requirements on the performance of atmospheric transport models. Improving the accuracy of these models should receive high priority, which calls for a closer collaboration between experts in atmospheric dynamics and tracer transpor

Four years tracking unrevealed topological changes in the african interdomain

Despite extensive studies on the Internet topology, little is still known about the AS level topology of the African Internet, especially when it comes to its IXP substrate. The main reason for this is the lack of vantage points that are needed to obtain the proper information. From 2013 to 2016, we enhanced the RIPE Atlas measurement infrastructure in the region to shed light on both IPv4 and IPv6 topologies interconnecting local ISPs. We increased the number of vantage points in Africa by 278.3% and carried out measurements between them at random periods. To infer results that depict the behavior of ISPs in the region, we propose reproducible traceroute data analysis techniques suitable for the treatment of any set of similar measurements. We first reveal a large variety of ISP transit habits and their dependence on socio-economic factors. We then compare QoS within African countries, European countries, and the US to find that West African networks in particular need to promote investments in fiber networks and to implement traffic engineering techniques. Our results indicate the remaining dominance of ISPs based outside Africa for the provision of intra-continental paths, but also shed light on traffic localization efforts. We map, in our traceroute data, 62.2% of the IXPs in Africa and infer their respective peers. Finally, we highlight the launch of new IXPs and quantify their impacts on end-to-end connectivity. The study clearly demonstrates that to better assess interdomain routing in a continent, it is necessary to perform measurements from a diversified range of vantage points.The work done by Rodérick Fanou was funded by IMDEA Networks Institute as part of the project “Mapping and Measuring the African Internet”. Francisco Valera has been partially funded by the European Commission under FP7 project LEONE (FP7-317647).Publicad

Toward accurate CO_2 and CH_4 observations from GOSAT

The column-average dry air mole fractions of atmospheric carbon dioxide and methane (X_(CO_2) and X_(CH_4)) are inferred from observations of backscattered sunlight conducted by the Greenhouse gases Observing SATellite (GOSAT). Comparing the first year of GOSAT retrievals over land with colocated ground-based observations of the Total Carbon Column Observing Network (TCCON), we find an average difference (bias) of −0.05% and −0.30% for X_(CO_2) and X_(CH_4) with a station-to-station variability (standard deviation of the bias) of 0.37% and 0.26% among the 6 considered TCCON sites. The root-mean square deviation of the bias-corrected satellite retrievals from colocated TCCON observations amounts to 2.8 ppm for X_(CO_2) and 0.015 ppm for X_(CH_4). Without any data averaging, the GOSAT records reproduce general source/sink patterns such as the seasonal cycle of X_(CO_2) suggesting the use of the satellite retrievals for constraining surface fluxes

Improved water vapour spectroscopy in the 4174-4300 cm⁻¹ region and its impact on SCIAMACHY HDO/H₂O measurements

The relative abundance of the heavy water isotopologue HDO provides a deeper insight into the atmospheric hydrological cycle. The SCanning Imaging Absorption spectroMeter for Atmospheric CartograpHY (SCIAMACHY) allows for global retrievals of the ratio HDO/HO in the 2.3 micron wavelength range. However, the spectroscopy of water lines in this region remains a large source of uncertainty for these retrievals. We therefore evaluate and improve the water spectroscopy in the range 4174–4300 cm⁻¹ and test if this reduces systematic uncertainties in the SCIAMACHY retrievals of HDO/H₂O. We use a laboratory spectrum of water vapour to fit line intensity, air broadening and wavelength shift parameters. The improved spectroscopy is tested on a series of ground-based high resolution FTS spectra as well as on SCIAMACHY retrievals of H2O and the ratio HDO/H₂O. We find that the improved spectroscopy leads to lower residuals in the FTS spectra compared to HITRAN 2008 and Jenouvrier et al. (2007) spectroscopy, and the retrievals become more robust against changes in the retrieval window. For both the FTS and SCIAMACHY measurements, the retrieved total H₂O columns decrease by 2–4% and we find a negative shift of the HDO/H₂O ratio, which for SCIAMACHY is partly compensated by changes in the retrieval setup and calibration software. The updated SCIAMACHY HDO/H₂O product shows somewhat steeper latitudinal and temporal gradients and a steeper Rayleigh distillation curve, strengthening previous conclusions that current isotope-enabled general circulation models underestimate the variability in the near-surface HDO/H₂O ratio

Precipitable water column retrieval from GOME data

We investigate the retrieval of terrestrial precipitable water columns using a new spectral fitting method applied to Global Ozone Monitoring Experiment (GOME) data. The method is an optical absorption spectroscopy technique and employs a new approach to the opacity sampling of absorption line spectra which we apply to a little-studied visible band between 585 and 600 nm. The GOME-retrieved columns are compared with data from the European Center for Medium-Range Weather Forecasts for different orbits and show good agreement. The new retrieval algorithm is sensitive to the temperature and pressure dependence of absorption lines in general and may be easily applied to spectra of trace gases other than water vapor