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Number of results: 74
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Abstract

The average grades of copper mines are dropped by extracting high grade copper ores. Based on the conducted studies in the mine field, the uncertainty of economic calculations and the insufficiency of initial information is observed. This matter has drawn considerations to processing methods which not only extracts low grade copper ores but also decreases adverse environmental impacts. In this research, an optimum cut-off grades modelis developed with the objective function of Net Present Value (NPV) maximization. The costs of the processing methods are also involved in the model. In consequence, an optimization algorithm was presented to calculate and evaluate both the maximum NPV and the optimum cut-off grades. Since the selling price of the final product has always been considered as one of the major risks in the economic calculations and designing of the mines, it was included in the modeling of the price prediction algorithm. The results of the algorithm performance demonstrated that the cost of the lost opportunity and the prediction of the selling price are regarded as two main factors directed into diminishing most of the cut-off grades in the last years of the mines’ production.
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Abstract

The separation or beneficiation processes are conducted in many devices and concern many various types of minerals and raw materials. The aim of conducting these processes is always to achieve the best possible results allowing as much of the useful component as possible to be obtained by maintaining reasonable costs of the process. Therefore, it is important to have the possibility to monitor the process effects and to have efficient tools to evaluate the course of it. Generally, the ore’s ability to partition into concentrate and tailings is called its efficiency, upgradeability etc. It can be said that there is no unambiguous measure of upgradeability and there are many factors in use which enable to evaluate it qualitatively. Among them are such commonly known parameters as: recovery, losses, yield, upgrading ratio and many others. They are based on three principal parameters that is the average content of the useful component α, the contents of this component in concentrate β and the contents of this component in tailings ϑ. For a given ore (assuming that α = constant), the multi-product separation results can be treated as points of a trajectory located on the surface of factor w in a three dimensional space (β, ϑ, w). The course of the trajectory depends on the ore petrographic and mineralogical properties preparation for the process. For these reasons, searching for optimal (potential) possibilities of the ore is relative, which is presented in the example of Halbich, Fuerstenau and Madej upgrading curves. Such curves are efficient tools to evaluate the course of a separation (beneficiation) process and each of their types allow the effects to be shown in different perspective. Apart from this, they allow also the optimal feed conditions to conduct a certain process with aim of achieving the expected results to be found. Furthermore, the effect of the ore preparation on the flotation results, on the sum of recoveries of the useful component in concentrate and residual recovery in tailings is presented in the paper. The results indicated that any additional contamination of concentrate should be taken into account during the organization of the flotation process. In this way, the results of fractionated flotation have much valuable information to establish the course of the process.
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Abstract

Polish brines are highly mineralized and can potentially be used for recovery of selected useful elements such as magnesium and potassium. They also contain a number of other elements, including iodine, bromine, boron, and strontium. The results of the examination of the chemical composition of groundwater from the Mesozoic formations (bromine, iodine, lithium, magnesium, and strontium content) of northern and central Poland were analyzed. The basic statistical parameters of the content of these elements (Br, I, Mg) in brines of the Triassic, Jurassic, and Cretaceous deposits and the content of lithium and strontium in waters of the entire Mesozoic formations were determined. In order to indicate aquifers that are the most suitable for the recovery of bromine, iodine, lithium, magnesium, and strontium, the relationship between concentrations and the depth of retention and dependencies between selected chemical components of these waters were analyzed. It has been found that the mineralization and concentrations of magnesium, bromine, and iodine increase with the age of aquifers, where these waters occur. Triassic waters are the most prospective for bromine and magnesium recovery among all analyzed aquifers. Furthermore, a relationship between the content of bromine, strontium, and magnesium has also been observed. The increase in the content of individual elements observed for lithium, strontium, and bromine with the increasing depth indicates a potential abundance of waters occurring at significant depths. The presented analysis is an approximation of the content of bromine, iodine, lithium, magnesium, and strontium; however, it may be the basis for further studies on the perspectives of using brines from the Mesozoic deposits of central and northern Poland as a source of chemical raw materials.
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Abstract

Due to the fact that the landfill deposition of municipal waste with the higher heating value (HHV) than 6 MJ/kg in Poland is prohibited, the application of waste derived fuels for energy production seems to be good option. There is a new combined-heat-and-power (CHP) plant in Zabrze, where varied solid fuels can be combusted. The formation of ashes originating from the combustion of alternative fuels causes a need to find ways for their practical application and demands the knowledge about their properties. Therefore, the present work is devoted to studying the co-combustion of solid recovered fuel (SRF) and coal, its impact on fly ash quality and the potential application of ashes to synthesis zeolites. The major objectives of this paper is to present the detail characteristics of ash generated during this process by using the advanced instrumental techniques (XRF, XRD, SEM, B ET, TGA). The co-combustion were carried out at 0.1 MWth fluidized bed combustor. The amount of SRF in fuel mixture was 1, 5, 10 and 20%, respectively. The focus is on the comparison the ashes depending on the fuel mixture composition. Generally, the ashes characterise high amounts of SiO2, Al2O3 and Fe2O3. It is well observed, that the chemical composition of ashes from co-combustion of blends reflects the amount of SRF addition. Considering the chemical composition of studied ashes, they can be utilize as a zeolites A. The main conclusions is that SRF can be successfully combusted with coal in CFB technology and the fly ashes obtained from coal + SRF fuel mixtures can be used to synthesis zeolites.
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Abstract

The optimization of cut-off grades is a fundamental issue for metallic ore deposits. The cut-off grade is used to classify the material as ore or waste. Due to the time value of money, in order to achieve the maximum net present value, an optimum schedules of cut-off grades must be used. The depletion rate is the rate of depletion of a mineral deposit. Variable mining costs are to be applied to the really excavated material, as some of the depletion can be left in-situ. Due to access constraints, some of the blocks that have an average grade less than the determined cut-off grade are left in-situ, some of them are excavated and dumped as waste material. Naturally, variable mining costs should be applied to the blocks of a mineral deposit that are actually excavated. The probability density function of an exponential distribution is used to find the portion of the depletion rate over the production rate that is to be left in-situ. As a result, inverse probability density function is to be applied as the portion of the depletion rate over the production rate that is to be excavated and dumped. The parts of a mineral deposit that are excavated but will be dumped as waste material incur some additional cost of rehabilitation that is to be included in the algorithm of the cut-off grades optimization. This paper describes the general problem of cut-off grades optimization and outlines the further extension of the method including various depletion rates and variable rehabilitation cost. The author introduces the general background of the use of grid search in cut-off grades optimization by using various depletion rates and variable rehabilitation cost. The software developed in this subject is checked by means of a case study.
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Abstract

Planning in a mining enterprise is a complex and multifaceted action. For this reason, it is necessary to provide its proper organisation and adjust it to the specific conditions of conducting underground mining extraction. The prepared plans must make up a cohesive internal system, unambiguously determining the manner, range and safety requirements of the conducted extraction. In the most general manner, the various types of plans developed by organisational units of mining enterprises can be divided based on the timeframe, type, scope and object of planning. These are strategic plans, tactical plans and subject-based plans. The aim of the article is to present the issue of production planning in a mining enterprise and for the preparation of such a plan, first and foremost, information about, among other things, applicable legal regulations, market conditions and the specificity of a mining enterprise are necessary. Underground extraction of black coal deposits must be conducted while respecting the rules of sustainable development which satisfies current needs, without compromising the ability to satisfy the needs of future generations. Due to the specific nature of mining production, manifested, among other things, by such features as the diversity of conditions for conducting the activity, resulting from the changing geological-mining conditions of the deposit, low flexibility of the production process, associated with the impossibility to conduct alternative production and a very long-lasting investment process, planning the course and magnitude of production in a mining enterprise must proceed with the highest possible diligence. One should take into account a wide range of presented environmental, organisational and technical conditions, deciding about the safety and correctness of the course of the assumed production activities. However, in order to make them economically feasible and produce satisfying results in that regard, it is also necessary to analyse them carefully with respect to financial outcomes
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Abstract

The use of biomass in the energy industry is the consequence of ongoing efforts to replace Energy from fossil fuels with energy from renewable sources. However, due to the diversity of the biomass, its use as a solid fuel generates waste with diverse and unstable chemical composition. Waste from biomass combustion is a raw material with a very diverse composition, even in the case of using only one type of biomass. The content of individual elements in fly ash from the combustion of biomass ranges from zero to tens of percent. This makes it difficult to determine the optimal recovery methods. The ashes from the combustion of biomass are most commonly used in the production of building materials and agriculture. This article presents the elemental composition of the most commonly used biomass fuels. The results of the analysis of elemental composition of fly ashes from the combustion of forest and agricultural biomass in fluidized bed boilers used in the commercial power industry were presented. These ashes are characterized by a high content of calcium (12.3–19.4%), silicon (1.2–8.3%), potassium (0.05–1.46%), chlorine (1.1–6.1%), and iron (0.8–6.5%). The discussed ashes contained no sodium. Aluminum was found only in one of the five ashes. Manganese, chromium, copper, nickel, lead, zinc, sulfur, bismuth, titanium and zirconium were found in all of the examined ashes. The analysis of elemental composition may allow for a preliminary assessment of the recovery potential of a given ash.
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Abstract

The functioning of European economies and societies requires a stable and sustainable supply of mineral resources. For 10 years now EU has been developing raw materials initiative to secure European minerals supply. In many cases, areas with known or hypothetic mineral resources, are not sufficiently valued by society and authorities, remain unprotected and face competing land uses with the risk of becoming sterilized. MINATURA 2020 project was born out of a need to develop a harmonised framework which allow a common way of identifying “mineral deposits of public importance” (MDoPI) and their safeguarding via land use planning. The project has left a useful set of guidelines and proposals how to advance on the creation of a European network of MDoPIs to avoid sterilization of “deposits worth safeguarding”. In Poland, the need for legal protection of mineral deposits has been discussed intensively in recent years. Various proposals aimed at better system of mineral deposits safeguarding, especially those which should be recognized as of public importance, have been proposed. However, until now only a few coal deposits were recognized as strategic. Currently, the Polish National Mineral Policy is under preparation. Its overriding objective is to provide access to the necessary minerals, also in the longterm perspective. It assumes among others activities aimed at protection of mineral deposits regarding land use planning system. Paper presents scope and general results of MINATURA2020 project, with details on MINATURA2020 methodology implementation in Poland, Project of the Polish National Mineral Policy with its objectives and key pillars, position of MDoPIs in this Project, and – finally – expected future steps related to MDoPI safeguarding in EU and in Poland.
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Abstract

Overseas mining investment generally faces considerable risk due to a variety of complex risk factors. Therefore, indexes are often based on conditions of uncertainty and cannot be fully quantified. Guided by set pair analysis (SPA) theory, this study constructs a risk evaluation index system based on an analysis of the risk factors of overseas mining investment and determines the weights of factors using entropy weighting methods. In addition, this study constructs an identity-discrepancycontrary risk assessment model based on the 5-element connection number. Both the certainty and uncertainty of the various risks are treated uniformly in this model and it is possible to mathematically describe and quantitatively express complex system decisions to evaluate projects. Overseas mining investment risk and its changing trends are synthetically evaluated by calculating the adjacent connection number and analyzing the set pair potential. Using an actual overseas mining investment project as an example, the risk of overseas mining investment can be separated into five categories according to the risk field, and then the evaluation model is quantified and specific risk assessment results are obtained. Compared to the field investigation, the practicability and effectiveness of the evaluation method are illustrated. This new model combines static and dynamic factors and qualitative and quantitative information, which improves the reliability and accuracy of risk evaluation. Furthermore, this evaluation method can also be applied to other similar evaluations and has a certain scalability.
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Abstract

The purpose of the research was mapping, inventorization, and valorization of coal mining waste dumps from the mines of JSW SA company, for the needs of recovery of coal from the dump material as well as the reclamation and management of examined facilities. The valorization of post-mining waste dumps has been carried out using a methodology which considers the problems of reclamation, management, accessibility of the dumps as well as environmental hazards connected with disposing of mining and preparation wastes on the ground surface. An inventorization of 10 coal mining waste dumps coming from 6 mines of JSW SA including in their range 7 deposits: Borynia, Jastrzębie, Zofiówka, Budryk, Knurów, Szczygłowice and Pniówek was carried out. The source material within the localization of particular dumps was obtained from archival materials coming from coal mines and municipalities where the dumps are located. Verified data has been drawn on topographical map, which results in the map of coal mining waste dumps. The results of the valorization of the dumps comprise the defining of: the name of the dump, state of the dump, surface of the dump, accessibility, name of the coal mine from where the wastes come from, type of technical and biological reclamation and possibilities of coal recovery, which have been brought on the drawn map. Basing on collected and elaborated data, an attempt of defining of potential possibilities of recovery of coal from the dumps and connection of coal quality in the deposits of JSW SA and in waste material was made. The results of the research showed that in spite of preliminary information that a majority of the investigated dumps may be considered as potential facilities for coal recovery, ultimately the recovery is economically justified only in several cases (5 facilities).
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Abstract

Washing is very popular technological operation removing clay particles from aggregates. The amount of mineral washing sludges increases. Besides filling the excavations, there is no common method of their utilization. The usage of sludges from washing aggregates in building ceramics might be environmentally friendly way to utilize them. This paper presents laboratory research on two type of sludges: from dolomite and limestone aggregates washing. Selected properties of sludges such as water content, particle size distribution (sieve and areometric method), chemical composition (XRF), mineral composition (XRD), thermal properties (STA/EGA, dilatometry, heating microscopy) and stability of fired materials during steam exposure were determined. It was found that dolomite sludge contains more clay minerals and less carbonates, it is more finely grained than limestone sludge. Limestone sludge has large fluctuations in water content and has high content of potentially hazardous calcite grains. During heating up to 1300°C of both dried sludges decarbonation and sintering take place. Dolomite sludge softens, melts and flows below 1300°C. After firing sludges at 1000°C material made of limestone sludge is not resistant to steam. The obtained result suggests that dolomite sludge can be used in building ceramics technology without processing as main component of ceramic mass. Limestone sludge have to be ground before its application in building ceramic materials. Results suggest that it can not be used as the main raw material in ceramic masses, but only as an additive.
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Abstract

Widespread opinion holds that calcareous rocks have limited suitability for use in the production of aggregates and stone products having adequate frost resistance. However, some of the rocks, in particular those from earlier geological periods, provide a promising alternative to silicate rocks. The paper presents results of the analysis of Devonian carbonate rock originating from two selected mines in the Swietokrzyskie region. The examined mines extract limestone from two different deposits of the same age. The rock samples are collected from beds lying at different depths, distinct in texture and color in macroscopic examination. It was found that despite the changes in bulk density, porosity and absorption, all the examined samples were frost resistant. Using the Differential Analysis of Volumetric Strain method, the content of ice formed in the pore spaces was determined. In addition, the ratio of the content of water capable of freezing to the total pore volume, and the total amount of water absorbed due to capillary action in rock samples soaked in water, were analyzed. In all cases, it was revealed that the destructive action of freezing water was weakened due to a relatively low content of water capable of freezing and a substantial volume of pores that are not filled with water in capillary absorption. It is extremely important to be able to classify the available rock material. The generally adopted methods, including absorptivity tests, do not allow for precise categorization. In the investigations, the authors focused on the analysis of the basic factors that are decisive for rock durability, including bulk density, pore filling level and volume absorption. The authors do not correspond compressive strength and resistance to abrasion as this will be the subject of further research.
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Abstract

At present, with the increase of production capacity and the promotion of production, the reserves of most mining enterprises under the original industrial indexes are rapidly consumed, and the full use of low-grade resources is getting more and more attention. If mining enterprises want to make full use of low-grade resources simultaneously and obtain good economic benefits to strengthening the analysis and management of costs is necessary. For metal underground mines, with the gradual implementation of exploration and mining projects, capital investment and labor consumption are dynamic and increase cumulatively in stages. Consequently, in the evaluation of ore value, we should proceed from a series of processes such as: exploration, mining, processing and the smelting of geological resources, and then study the resources increment in different stages of production and the processing. To achieve a phased assessment of the ore value and fine evaluation of the cost, based on the value chain theory and referring to the modeling method of computer integrated manufacturing open system architecture (CIMOSA), the analysis framework of gold mining enterprise value chain is established based on the value chain theory from the three dimensions of value-added activities, value subjects and value carriers. A value chain model using ore flow as the carrying body is built based on Petri nets. With the CPN Tools emulation tool, the cycle simulation of the model is carry out by the colored Petri nets, which contain a hierarchical structure. Taking a large-scale gold mining enterprise as an example, the value chain model is quantified to simulate the ore value formation, flow, transmission and implementation process. By analyzing the results of the simulation, the ore value at different production stages is evaluated dynamically, and the cost is similarly analyzed in stages, which can improve mining enterprise cost management, promote the application of computer modeling and simulation technology in mine engineering, more accurately evaluate the economic feasibility of ore utilization, and provide the basis for the value evaluation and effective utilization of low-grade ores.
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Abstract

The aim of the article is to present the selected results of analytical investigations concerning possible directions of reducing the unit production costs in the mining company together with some results of practical calculations. The investigations emphasize the role of the rate of utilising the production capacity leading to reducing the unit production costs. The main component having an essential influence on the unit production costs are the fixed unit costs. Two basic indices of a crucial meaning for searching for possibilities leading to decreasing the unit production costs are assumed. The first index (w1) is a measure of the rate of utilising the production capacity, the second one (w2) concerns the fixed costs coincided with the unit of the production capacity. Theoretical considerations concerning the mathematical modelling of the unit production costs as the values depending on the rate of utilising the production capacity and the fixed costs coincided with the production capacity unit, are presented in the first part of the paper. The rationalisation criteria of the mine unit production costs are formulated. These criteria can constitute the elements of restructuring program for the mining company. The calculation example with the use of the practical input data shows the impact of the rate of utilising the production capacity on the mine unit production costs. In the example two variants of annual working time are taken into account. Results of appropriate calculations are presented and analysed in an aspect of reducing unit costs of production as a result of increasing rate of utilising the mine production capacity.
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Abstract

The article addresses the issue of conditions that the borrower is obliged to fulfill during the crediting process. These terms, the so-called covenants are built into credit agreements and are aimed at limiting banks’ risk when financing business entities. However, at the same time, covenants constitute conditions limiting the scope of use of bank loans. Covenants are very diverse. The principle hypothesis of the study assumes that the covenants differ according to the type of credit and the characteristic of the industry and the financial situation of the enterprise. In order to examine the hypothesis, an analysis of 25 credit agreements in three corporations and their subsidiaries was undertaken. These entities belong to fuel, mining and metallurgical sectors. At the same time, we observe the extent to which these covenants were kept during four quarters of 2016 and two quarters of 2017. Due to the confidentiality of the data contained in the loan agreements, the names of groups and their companies were kept confidential at the request of their management. Studies have also shown that abiding by non-financial covenants has been more difficult than abiding by financial covenants. In covenants, several contracts stipulated that a company cannot freely dispose fixed assets, restructure them or use leased assets which hinders the use of those asset to repay debt. One major obstacle was the fact that the company could not undertake any additional business beyond the existing one. This hindered the diversification of companies’ activities, which would improve their competitive position on the market. The author intends to conduct further research on covenants to highlight their flexible use and to increase the availability of bank loans to business entities.
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Abstract

During drilling through aquifers using the rotary drilling method with drilling fluid application, the phenomenon of formation clogging in near-well zone takes place. This leads to physical changes in pore spaces in consequence of the deposition solid phase particles originating from the drilling fluid. Due to this fact, filtration velocity in the clogged zones of the aquifer formation decreases, which results in increased pressure drawdown and decreased well hydraulic efficiency. Therefore, it causes a reduction of the well total capacity. The article consists of studies connected to the development of the mud which will constitute the basis for a complex mud system intended for hydrogeological drilling in different encountered geological conditions. In the framework of laboratory research, technological parameters of six, commonly applied in oil and gas industry, polymer agents as well as new agent developed at the Drilling, Oil and Gas Faculty AGH-UST in Krakow were examined. The undertaken studies showed that the new agent, marked as CAGEx, provides the required technological parameters and can be applied as a base for drilling muds intended for hydrogeological drilling. The undertaken industrial research of the new CAGEx drilling mud carried out while drilling water intake well, confirmed the great stability of its technological parameters as well as insignificant influence on rock permeability damage in filter zone. The water intake well is characterized by high hydraulic efficiency and does not require additional activation treatment.
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Abstract

Ore and non-ore mineralization in cracks filled with hydrocarbons in the dark grey Upper-Devonian limestone has been found in the Józefka quarry of Upper Devonian limestone and dolomite near the Górno village near Kielce at Holy Cross Mts. Poland. Hydrocarbons in the liquid form and iron and copper sulphides appears hear in the fault zone as joints filling. The wall rocks are impregnated by hydrocarbons giving them black color. Hydrocarbon impregnations appears also following the bedding planes The coexistence of ore mineralization and hydrocarbon suggests their common origin and migration from deep-seated sources, that may be the Silurian Ordovician or Lower to Middle Devonian black shales. The metallic-hydrocarbon compounds were suggested as metals carrier. Ore and non-ore mineralization in cracks filled with hydrocarbons in the dark grey Upper-Devonian limestone has been found in the Józefka quarry of Upper Devonian limestone and dolomite near the Górno village near Kielce at Holy Cross Mts. Poland. Hydrocarbons in the liquid form and iron and copper sulphides appears hear in the fault zone as joints filling. The wall rocks are spotty impregnated by hydrocarbons giving them black color. Hydrocarbon impregnations appears also following the bedding planes The coexistence of ore mineralization and hydrocarbon suggests their common origin and migration from deep-seated sources, that may be the Silurian Ordovician or Lower to Middle Devonian black shales. The metallic-hydrocarbon compounds were suggested as metals carrier.
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Abstract

Control of the technological processes of coal enrichment takes place in the presence of wide disturbances. Thus, one of the basic tasks of the coal enrichment process control systems is the stabilization of coal quality parameters at a preset level. An important problem is the choice of the controller which is robust for a variety of disturbances. The tuning of the controller parameters is no less important in the control process . Many methods of tuning the controller use the dynamic characteristics of the controlled process (dynamic model of the controlled object). Based on many studies it was found that the dynamics of many processes of coal enrichment can be represented by a dynamic model with properties of the inertial element with a time delay. The identification of object parameters (including the time constant) in industrial conditions is usually performed during normal operation (with the influence of disturbances) from this reason, determined parameters of the dynamic model may differ from the parameters of the actual process. The control system with controller parameters tuned on the basis of such a model may not satisfy the assumed control quality requirements. In the paper, the analysis of the influence of changes in object model parameters in the course of the controlled value has been carried out. Research on the controller settings calculated according to parameters T and τ were carried out on objects with other parameter values. In the studies, a sensitivity analysis method was used. The sensitivity analysis for the three methods of tuning the PI controller for the coal enrichment processes control systems characterized by dynamic properties of the inertial element with time delay has been presented. Considerations are performed at various parameters of the object on the basis of the response of the control system for a constant value of set point. The assessment of considered tuning methods based on selected indices of control quality have been implemented.
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