Mining Costs Research Articles

Effect of curing temperature on the mechanical properties and pore structure of cemented backfill materials with waste rock-tailings

In order to reduce the cost of deep mining in Guangxi Gaofeng Mine, the feasibility of underground waste rock used for backfill and was analyzed. The tailings and waste rock taken from Gaofeng Mining Industry had been selected for comparative tests, different ratio of waste rock and tailings and curing temperatures were set, the effect of different conditions on the porosity and strength of waste rock and tailings cemented backfill was investigated. Study indicates that the macroscopic mechanical properties of the backfill are the external response of its microstructure, and the change of the microstructure of the backfill is the essential reason for the change of its mechanical properties. when the waste rock-tailings ratio is 6:4 or 7:3, the USC increases with the increase of the curing temperature; while the waste rock-tailings ratio is 8:2 or 9:1, the USC tends to increase and then decrease with the increase of the curing temperature, where 40℃ is the turning point. In deep mines of Gaofeng Mine, ratio of waste rock and tailings of 9:1 is preferred when the temperature is around 40 °C, while ratio of waste rock and tailings of 6:4 is more effective at deeper depths around 50 °C.

Optimization of mining methods for deep orebody of large phosphate mines

Introduction: Taking Yunnan Phosphate Group Co., Ltd. Kunyang Phosphate Mine No. 2 as the engineering background, this study aims to explore mining methods for deep ore bodies in phosphorus mines. Three mining schemes, namely open-pit mining, open-pit deep concave mining, and underground mining, were carefully selected for optimization. This article thoroughly analyzes the three schemes from various perspectives, including technical, economic, safety, and other aspects.Methods: The assessment of these aspects was conducted using the entropy weighted TOPSIS method. The technical aspects focused on evaluating the mining methods employed in each scheme. The economic aspects considered factors such as initial investment, resource recovery rate, phosphate content, production scale, infrastructure, and mining costs. Safety aspects took into account transportation safety and production safety. Additionally, the analysis considered environmental impact as one of the key factors. In total, 10 indicators were quantified to provide a comprehensive evaluation. To assess the schemes, the positive and negative ideal distances (Di+, Di−) and the relative proximity (Ci) for open-pit mining, open-pit deep concave mining, and open-pit to underground mining were calculated. These calculations helped to determine the relative performance of each scheme.Results: The relative closeness values (Ci) for Scheme 1, Scheme 2, and Scheme 3 are determined as 1.00, 0.09, and 0.68, respectively.The evaluation results indicate that the relative closeness (Ci) for open-pit mining in Scheme 1 is 1.00, for open-pit deep concave mining in Scheme 2 is 0.09, and for underground mining in Scheme 3 is 0.68. Through comparison and analysis of these results, it can be concluded that open-pit mining is the most optimal method. However, considering the fact that the open-pit portion of Kunyang Phosphate Mine No. 2 has already been extensively mined, the study recommends underground mining as the best mining plan for the phosphate mine.Discussion: By applying the entropy weight TOPSIS method to underground mining, this study overcomes the challenge of transitioning from qualitative to quantitative analysis for selecting mining methods. The mathematical approach enables the presentation of optimal mining techniques in a more precise manner. Through comparison of relative closeness, an optimal solution can be selected. This method holds significant value not only for selecting suitable mining methods for phosphorus mines but also for choosing optimal solutions for underground mining methods, drainage, ventilation, and other relevant considerations.

Study on filling mining technology for gently inclined thin to medium thick phosphorus deposits

This study is grounded in research conducted at the Kunyang Phosphate Mine No. 2, a Chinese open-pit phosphate mining enterprise owned by the Yunnan Phosphate Group Co., Ltd. Due to the small inclination angle and the presence of weak interlayers in the middle of the gently inclined thin to medium thick phosphate ore layer, mining such ore bodies cannot rely on self weight migration, making roof management difficult and mining costs high technical challenges. The methods utilized on-site research, engineering comparisons, and theoretical analysis experiments to address the gently inclined phosphorus deposits. Based on the actual technical and economic conditions of current phosphorus mines, the advantages, disadvantages, and practical conditions of upward horizontal layered filling mining method, upward horizontal layered drift filling mining method, and pseudo inclined segmented strip filling mining method are compared. Priority should be given to using the pseudo inclined segmented strip method as the main method for mining, supplemented by the upward horizontal layered filling method in the panel area. And theoretical calculation methods were applied to obtain various numerical values of the filling capacity of the 2 million t/a mine filling test section, providing technical support for the mining design and equipment selection of the filling test system. The relevant research results can provide guidance for the selection of mining methods for gently inclined thin to medium thick phosphate deposits with an average inclination angle of 15°. The theoretical calculation method used can provide technical guidance for the filling system and filling equipment.

Study of the impact of the open pit productivity on the economic indicators of mining development

The article studied the issue of improving the scientific and methodological base in the field of design and planning of open-pit mining by developing new and adjusting existing methods for determining the ore productivity of an open-pit, which should take into account the interconnection between the mining schedule and the productivity of an open-pit for ore, based on the condition for ensuring the standard volume of finished to the extraction of reserves. When choosing the production of an open-pit for ore, it is necessary to take into account the impact of the interconnection between the schedule of mining and production, based on the conditions of regulatory regulation of the volume of mining for the excavation of reserves, on the cost of ore mining and concentrate production. With an increase in ore productivity, the cost of ore mining, as well as the cost of production of concentrate reduction. At the same time, the very possible productivity of the open-pit for especially minerals is achieved, the economic efficiency of the development of deposits is achieved with the chosen direction of the open-pit. A decrease in productivity for a common mineral by 20 and 40% entails a decrease in profit from the development of the deposit by 10 and 20%, respectively. It has been determined that an increase in the slope angle of the working side of the open-pit significantly reduces the economic efficiency of the development of the deposit due to the fact that the operation of the open -pit with a large slope angle entails not only a decrease in the current stripping ratios as a result of an improvement in the mining schedule, but also a decrease in ore productivity, which reduces the present value of marketable products due to an increase in the period of development of the deposit. The results of the studies performed can be used by design organizations and mining enterprises in determining the ore productivity of an open-pit.

The Environmental Footprint of Bitcoin Mining Across the Globe: Call for Urgent Action

AbstractBased on a multi‐attribute assessment of the environmental impacts and challenges associated with global Bitcoin (BTC) mining activities around the globe, we call for urgent action by the scientific, policy, and advocacy communities. The worldwide BTC mining network consumed 173.42 TWh of electricity during the 2020–2021 period, bigger than the electricity consumption of most nations. The mining process emitted over 85.89 Mt of CO2eq in the same timeframe, equivalent to the emission caused by burning 84 billion pounds of coal or running 190 natural gas‐fired power plants. The environmental footprint of BTC mining is not limited to greenhouse gas emissions. In 2020–2021, the global water footprint of BTC mining was about 1.65 km3, more than the domestic water use of 300 million people in rural Sub‐Saharan Africa. The land footprint of the global BTC mining network during this period was more than 1,870 square kilometers, 1.4 times the area of Los Angeles. These striking numbers highlight the heavy reliance of the BTC network on fossil fuels and natural resource‐intensive energy sources, resulting in major but unmonitored and unregulated environmental footprints. To mitigate the environmental costs of BTC mining, immediate policy interventions, technological advancements, and scientific research are crucial. Proposed measures include enhanced transparency, economic and regulatory tools, developing energy‐efficient alternative coins, and the adoption of greener blockchain validation protocols.

ANALISIS REALISASI BIAYA OPERASIONAL PENGUPASAN COAL GETTING KHUSUS ALAT UTAMA PENAMBANGAN DI PT DUTA ALAM SUMATERA SITE PT XYZ KABUPATEN LAHAT PROVINSI SUMATERA SELATAN

Mining activities will definitely require calculation in mining cost. Operational cost can effect the company’s revenue, so an analysis of operational costs is necessary. This study aimed to calculate the estimated production and actual production of coal getting in March 2023 and to calculate the operational costs of estimated production and actual production of coal getting in March 2023. The analysis process was carried out by determining the estimation and realization of coal getting production where the estimated production of coal getting was 35000 tons with 1 unit of digging equipment and 5 units of hauling equipment with operational costs for coal getting production incluiding the realization of diesel fuel of Rp76,926,810.00, oil of Rp500,000.00, operator salary of Rp5,400,000.00, repair/maintenance of Rp42,980,000.00, grease of Rp239,267.00, and Liugong Excavator filter of Rp300,000.00. those were lower than the estimated costs of diesel fuel of Rp103,647,600.00, oil of Rp4,000,000.00, operator salary of Rp10,800,000.00, repair/maintenance of Rp76,680,000.00, grease pf Rp3,800,000.00, and filters of Rp2,100,000.00. whereas for the Dongfeng Dump Truck, the actual costs of diesel was Rp25,000,000.00, oil cost was Rp360,000.00, operator salary cost was Rp25,000,000.00, spare parts cost was Rp270,000.00, grease cost was Rp656,355.00, filter cost was Rp300,000.00, and tires cost was Rp705,000.00 which were lower than the estimated cost of diesel fuel of Rp483,688,800.00, oil of Rp4,000,000.00, operator salary of Rp50,000,000.00, repair/maintenance of Rp76,680,000.00, grease of Rp3,800,000.00, filters of Rp2,100,000.00 and tires of Rp18,350,000.00. thus, the estmated operational cost was Rp777,589,300.00 and the realization was IDR 282,819,689.00.

Methodological approach to assessing influence of blasted rock fragmentation on mining costs

Methodological approach to assessing influence of blasted rock fragmentation on mining costs

B-159 Data Mining With the Bhattacharya Method as a Tool for Reference Interval Determination in Populations With Thyroid Disorders

Abstract Background Establishing a precise reference interval (RI) is crucial for laboratory diagnosis, population studies, and aiding physicians in patient follow-up treatment. Data mining and Bhattacharya analysis can be an efficient and cost-effective way to determine RIs for thyroid disorders based on large datasets. Bhattacharya analysis is a simple resolution method that detects distributions into Gaussian components. Unlike traditional reference interval studies using parametric or non-parametric statistics, Bhattacharya analysis does not exclude results from an “unhealthy” population before analysis. This study aimed to define the RI for thyroid-stimulating hormone (TSH) and free thyroxine (fT4) from three distinct regions in São Paulo, Brazil, using the Bhattacharya method. Methods The study was a 20-month retrospective analysis of a large laboratory database in São Paulo from February/2021 to September/2022. Individuals aged 21 or older with available TSH or fT4 results were selected, including only outpatient results. Three groups from different regions (R1, R2, R3) were studied and the indirect Bhattacharya method was used to determine each region’s RI values. The midpoint, upper and lower reference limits (URL and LRL), were calculated, and a data plot was created using Microsoft Excel. One-way ANOVA was used for multiple group comparisons and results with *P < 0.01 were considered statistically significant. Results A total of 234 903 TSH and fT4 records were obtained. The three groups showed significant differences in their mean age and TSH and fT4 results (P < 0.001). The mean age was 49.41 ± 16.9 for R1, 46.9 ± 9.6 for R2, and 53 ± 16 years old for R3. The average TSH value for all three regions was 2.44 µIU/mL (SD 0.18, CV 7.2%), and the average fT4 value was 1.17 ng/dL (SD 0.06, CV 4.7%). The central bin was selected for the best data distribution and close to the average or median for each group. The derived RIs for R1, R2, and R3 were compared for consideration of a common RI. Other criteria, such as the best bin size and at least four bins for the graph curve, were also applied. Altogether, Bhattacharya’s analysis identified the following estimates from all collection points for TSH and fT4: TSH Average LRL 0.43 µIU/mL (SD 0.07, CV 16.6%)/TSH Average URL 6.45 µIU/mL (SD 0.85, CV 13.1%)/TSH Average Range 6.03 µIU/mL (SD 0.88, CV 14.6%)/fT4 Average LRL 0.82 ng/dL (SD 0.07, CV 8.1%)/fT4 Average URL 1.47 ng/dL (SD 0.07, CV 4.4%)/fT4 Average Range 0.65 ng/dL (SD 0.02, CV 3.5%). 9.7% of individuals in R3 had results outside the accepted RIs for TSH and fT4, compared to R2 as a standard population with the lowest possibility of relevant thyroid disorders. Conclusion Bhattacharya’s non-parametric method could be useful to determine reference values and laboratory analysis of populations with distinct characteristics. The study highlights the importance of choosing the correct control group in comparison studies, and the potential bias in unifying distinct regions to determine RIs. The low cost of data mining makes it possible for nearby laboratories to perform similar studies using the Bhattacharya method to establish RI results suitable for specific patient populations.

IMPROVEMENT OF FOREST ROADS, CASE STUDY: THE ACCESS ROAD TO THE GOLIRAN COAL MINE IN MAZANDARAN PROVINCE, IRAN

Improvement of existing forest roads for easier access to mineral resources and operation is one of the national needs and a factor of economic and tourism development in the forest areas on the southern Coast of the Khazar Lake and in the Highlands of the northern provinces of Iran. Forest resource management can only be sustainable through a well-organized road network designed with optimal spatial planning and minimum environmental impacts. Improving the quality of forest roads leads to reducing mining and transport costs, and improving the livelihoods of the local people However, unscrupulous construction and improper maintenance could have adverse and irreparable effects. Environmental destruction should be minimized in the design and construction of forest roads and engineering principles should not be neglected in this regard. In the long run, Improved Road construction will have positive environmental impacts because road damage due to Erosion and Drift brings environmental damage in addition to economic and social injuries. One of the main factors in the stability and durability of roads is extensive drainage and stabilization of the road shell in inaccessible forest and mountain areas. This article examines environmental and engineering problems, sustainability, and impacts of drainage and stability in the construction and improvement of forest roads based on the access road to the Goliran coal mine in the highlands of Babol county in Mazandaran province, Iran.

RELATIONSHIP «RARE-EARTH METALS – ENERGY TRANSITION IN THE CONTEXT OF FULL CYCLE PROJECTS

The article examines the development of the rare earth industry in Russia. Russia has a significant resource base of this type of mineral raw materials, but it does not fully use the existing potential. Russia exports semi-products of low processing, and imports goods containing rare earth elements with high added value. The key problem of the industry is the insignificant domestic demand for rare earth metals. The growing interest in the world in renewable energy sources makes new opportunities for the development of the Russian rare earth industry and gives a chance for the transition of the Russian economy to a new technological order. At the heart of the policy to create demand for rare earth products within the country, the authors propose to use a theoretic approach based on the consideration of full-cycle projects. Three main features characterize this approach. Firstly, our approach is an extension of the traditional project approach and takes into account not so much the local aspects of a separate project for the extraction and processing of ore, but its integration into the country's economy through a system of intersectoral interactions (multiplicative effects). Secondly, as the demand for products within the country grows and the scale of the use of products based on rare earth metals expands, the process of “learning” is launched - the costs of mining, processing and production of final products are reduced. Thirdly, the approach proposes to consider rare earth ores in dumps as pseudo-financial assets with the ability to manage them as traditional economic asset

Carbon Emission Prediction Model for the Underground Mining Stage of Metal Mines

At present, the carbon emissions in China’s metal mining industry can be calculated based on the amount of energy consumed in the mining process. However, it is still difficult to predict the carbon emissions before implementation of mining engineering. There are no effective approaches that could reasonably estimate the amount of carbon emissions before mining. To this end, based on the ‘Top–down’ carbon emission accounting method recommended by the Intergovernmental Panel on Climate Change (IPCC), this study proposes a model to predict the greenhouse gases emitted in seven carbon-intensive mining stages, namely, drilling, blasting, ventilation, drainage, air compression, transportation, and backfilling. The contribution of this model is to enable a prediction of the accumulation of greenhouse gases based on the mining preliminary design of mine, rather than on the consumption of energy and materials commonly used in recent research. It also establishes the amount of carbon emissions generated by mining per unit cubic meter of ore rock as the minimum calculation unit for carbon emissions, which allows for the cost and footprint of carbon emissions in the mining process to become clearer. Then, a gold–copper mine is involved as a case study, and the greenhouse gas emissions were predicted employing its preliminary design. Among all the predicted results, the carbon emissions from air compression and ventilation are larger than others, reaching 22.00 kg CO2/m3 and 10.10 kg CO2/m3, respectively. By contrast, the carbon emissions of rock drilling, drainage, and backfilling material pumping are 5.87 kg CO2/m3, 6.80 kg CO2/m3, and 7.79 kg CO2/m3, respectively. To validate the proposed model, the calculation results are compared with the actual energy consumption data of the mine. The estimated overall relative error is only 5.08%. The preliminary predictions of carbon emissions and carbon emission costs in mining before mineral investment were realized, thus helping mining companies to reduce their investment risk.

Recovering Co3O4 from waste choline chloride/ethylene glycol electrolyte containing Co(II) ions along with solvent regeneration

Efficiently recovering critical metals from secondary resources is crucial to decreasing the environmental impact of mineral-resource mining and reducing production costs and process energy consumption. Herein, we propose a simple and comprehensive approach to recycle Co3O4 from waste choline chloride/ethylene glycol (named Ethaline) electrolyte containing Co(II) ions along with solvent regeneration. Through the rational coordination adjustment using water, [CoCl4]2− complex in the Ethaline-based electrolyte is transformed to [CoCl2(H2O)4]0 and [CoCl2(H2O)5]+ to facilitate precipitation separation. Adding oxalic acid (OA) as a precipitator can reach 97.1% cobalt recovery efficiency with a high value-added Co3O4 rod-like structure obtained by calcining the oxalate precipitate. In addition, the water-containing solvent can be regenerated via reduced pressure distillation with a high recovery efficiency of up to 98.0%. FT-IR and 1H NMR characterizations verify that the regenerated Ethaline exhibits good structural stability. Impressively, the proposed recovery path shows high recovery efficiencies for both cobalt and Ethaline in various practical Co(II) ion-containing electrolytes. This study establishes a novel technical pathway for the resource utilization of metal-bearing waste Ethaline electrolytes, which shows an excellent prospect in solvent recycling after metal processing.

Proof-of-Work Cryptocurrencies: Does Mining Technology Undermine Decentralization?

Does the proof-of-work consensus protocol serve its intended purpose of supporting decentralized cryptocurrency mining? To address this question, we develop a game-theoretical model in which miners first invest in hardware to improve the efficiency of their operations and then compete for mining rewards in a rent-seeking game. We show that centralization grows with heterogeneity in mining costs, but hardware capacity constraints prevent the most efficient miners from monopolizing the mining process. Investment leads to a more decentralized network unless larger miners have a significant comparative advantage in acquiring new hardware. Our model generates empirically supported implications: (i) mining centralization is countercyclical with respect to mining reward, and (ii) a change in mining reward leads to a less-than-proportional change in hash rates. This paper was accepted by David Simchi-Levi, Special Section of Management Science: Blockchains and Crypto Economics. Supplemental Material: The data file is available at https://doi.org/10.1287/mnsc.2023.4840 .

Integrating stochastic mine planning model with ARDL commodity price forecasting

Commodity price is of paramount importance to mine planning among other stochastic factors such as mining cost and geological uncertainties. Commodity price uncertainty is critical in the determining block values, and it has been incorporated into mine planning by simulation-based methodologies to deal with the effects of price uncertainty during the mining process. In this article, stochastic optimisation was undertaken using parametric minimum cut network flow algorithm for ultimate pit and pushback design, while stochasticity of commodity prices was incorporated into the planning using Autoregressive Distributed Lag (ARDL) simulation model. The push back design and cashflows in two scenarios, namely when the prices are going up and when the prices are going down, were investigated. Moreover, for each scenario, three types of price inputs were considered: (a) actual prices; (b) ARDL forecasted prices; and (c) stochastic prices generated from ARDL forecasted prices. The results of cashflows indicated that when commodity price moving up scenario, the ARDL forecasted prices underestimate the NPV by about 17% and the stochastic minimum cut underestimates the NPV by 72.27% compared to actual price. Similarly, for the price declining scenario, the ARDL forecasted prices underestimated the NPV by about 3% compared to the actual, while the stochastic minimum cut has an NPV value that is 277% of the actual value. Lastly the value of stochastic programming (VSP) was evaluated. The VSP was about 9.2 million dollars when the prices were going up, while the VSP was about 27.1 million dollars, when price was declining. Moreover, declining commodity price produced negative cashflows which indicate need for risk management with a recourse action to evert losses.

Assessing Geological and Mining Condition Nuisance and its Impact on the Cost of Exploitation in Hard Coal Mines with the Use of a Multi-Criterion Method

This article presents the use of a multi-criterion Analytic Hierarchy Process (AHP) method to assess geological and mining condition nuisance in longwall mining operations in selected coal mines in Poland. For this purpose, a methodology has been developed which was used to calculate the operational nuisance indicator (WUe) in relation to the cost of mining coal in individual longwalls. Components of the aggregate operational nuisance indicator include four sub-indicators: the natural hazards indicator (UZN), an indicator describing the seam parameters (UPZ), an indicator describing the technical parameters (UT) and an environmental impact indicator (UŚ). In total, the impact of 28 different criteria, which formed particular components of the nuisance indicators were analysed. In total 471 longwalls in 11 coal mines were analysed, including 277 longwalls that were mined in the period of 2011 to 2016 and 194 longwalls scheduled for exploitation in the years 2017 to 2021. Correlation analysis was used to evaluate the relationships between nuisance and the operating costs of longwalls. The analysis revealed a strong correlation between the level of nuisance and the operating costs of the longwalls under study. The design of the longwall schedule should therefore also take into account the nuisance arising from the geological and mining conditions of the operations. Selective operations management allows for the optimization of costs for mining in underground mines using the longwall system. This knowledge can also be used to reduce the total operating costs of mines as a result of abandoning the mining operations in entire longwalls or portions of longwalls that may be permanently unprofitable. Currently, underground mines do not employ this optimization method, which even more emphasizes the need for popularizing this approach.

Effects of fragmentation on production at Peak mine Midlands, Zimbabwe

Over the years, the cost of production at Peak Mine Midlands, Zimbabwe, has been high due to oversized rock fragments. This led to increased mining costs far above what was planned by the mine. Initial investigations showed that valuable production hours were lost in trying to deal with the oversized rock fragments at the draw points. This study was conducted at Peak Mine Midlands, Zimbabwe, on 1210 level. The methods used to assess the effects of fragmentation on production at the mine included visual assessment, analysis of the drill and blasting costs of the production data, 2D image analysis, sieve analysis, time and motion studies, analysis of the explosive’s consumption, mining blasting trials and post-mine blast experiments. The results show that the current ring hole designs used in the sublevel open stopes at Peak Mine do not give optimal particle size distribution after the primary blasts as the sieve analyses show that 50% of the sizes of materials at the draw points are larger than 1,000 mm. While 4 secondary blasts were budgeted per shift to reduce the sizes of the boulders to sizes that will pass through the grizzly’s sieves, 7 secondary blasts were done per shift and this led to about 75% increase in the cost of explosives consumed by the mine. The results also show that 35.96 minutes of production time were lost on each secondary blast conducted. Four trial blasts conducted on different ring hole patterns show that ring #1 which has a burden of 1.2 m instead of 1.8 m in the other ring holes led to a significant reduction in drilling and blasting costs from USD $33.79 in trial #4 (the control case) to $28.80 in trial #1. The sieve analyses also show that the optimal fragment sizes from primary blasts are in the range of X = +200 mm and X = +300 mm. So, the designed ring hole patterns in the sublevel open stopes should produce particles with sizes in the range of  150 mm and  +350 mm from the primary blasts.

Noble Metals in Recent Developments of Heterogeneous Catalysts for CO2Conversion Processes

AbstractFollowing the advances in capture technologies, CO2utilization associated with low‐cost renewable H2in catalytic hydrogenation is a promising strategy for reducing the carbon footprint of industrial processes by providing valuable chemicals and fuels. However, the scalability and economic viability of these processes will depend on the development of efficient catalysts. Noble metal‐based catalysts have been extensively reported in the last few years as highly effective in promoting CO2hydrogenation to various products. Although promising, the scarcity, high cost, and environmental impact of mining make it challenging to scale up these materials from bench to plant. Developing advanced synthesis and characterization methods is essential to control and understand active sites’ behavior during the reaction, providing high activity and durability. This review carefully summarizes the recently reported noble metal‐based heterogeneous catalysts for thermocatalytic conversion of CO2into methane, carbon monoxide, methanol, formic acid, higher alcohols, C2+hydrocarbons, and syngas through dry reforming of CH4, to draw the state‐of‐the‐art development in the field. Finally, we critically discuss the impact of these elements on catalyst properties, the challenges related to their implementation, and future research opportunities.

Dynamics of mining markets: Equilibrium implications for professional and casual miners

We design a simple equilibrium model to analyze the dynamics of the mining market in the presence of professional and casual miners. The model endogenously recovers two major unobservable drivers: the supply of computing power, and the dynamics of the fixed costs of mining. We calibrate the model to the market of Bitcoin and Ethereum and find that positive shocks to the supply of computing power (technological enhancements) translate into positive price shocks, and the benefits of these hikes are creamed off by professional miners. We also find that fixed costs are inversely related to technological enhancements, decrease at an exponential rate (which is twice as big for Bitcoin), and are the smallest during periods when professional miners have a monopoly.

PriRanGe: Privacy-Preserving Range-Constrained Intersection Query Over Genomic Data

Genomic data is being produced rapidly by both individuals and enterprises, and outsourcing this ever-increasing data into clouds is promising for cutting the cost of data owners and mining the wealth of genomic data at a larger scale. However, genome carries sensitive information about individuals, and it is challenging to securely and efficiently perform analysis on remotely hosted genomic databases. In this paper, we present a privacy-preserving range-constrained intersection query scheme on genomic data. To achieve security and efficiency, we propose a protocol to fulfill range-constrained intersection query, named PriRanGe. With PriRanGe, a client can securely query genomic data in a specific range in a database while keeping this whole process private. The security of our design targets genomic database confidentiality, query range/result confidentiality, and access pattern protection, and the advantage in efficiency is due to most employed primitives are symmetric. We thoroughly evaluated our design by security proof, experimental analysis and comparison to the state-of-the-art works, all of which support the conclusion that this design is both secure and fast.

More than Gold: Embodying the Human Cost of Mining in Maroon Popular Music

Abstract Maroons (descendants of Africans who escaped enslavement) have long been locked in an antagonistic relationship with the Surinamese government over gold-mining legislation and its reinforcement. This contentious topic includes complex debates over land rights and conflicting economic and environmental priorities. This article considers how three contemporary Maroon popular musicians have gone beyond stock metaphors about gold to reference local engagements with gold and the gold-mining industry. I introduce the concept, performative figuring, as a strategy whereby a speaker or performer uses their embodied presence to assert their rights and/or self-worth against practices and policies that threaten to undermine them.