Mining Costs Research Articles

Investment Project Analysis Pit CACD Block 8 Using Discounted Cash Flow (DCF): A Case Study of Pt. Berau Coal

PT Berau Coal which is located in Berau Regency, East Kalimantan Province. Pit C2 Block 8 Binungan Mining Operation Area 2 PT Berau Coal is a coal mining operation area with multi-seam characteristics with a slope of coal seams at intervals of 40 – 60 degrees. The characteristics of coal deposits are one of the considerations in the formation of coal mining designs in collaboration with other disciplines, including geotechnical, hydrology, safety and environment, as well as other aspects. PT Berau Coal faces several challenges, risks and uncertainties such as fluctuations in coal prices, production capacity, mining costs and related legal aspects. Therefore, mining planning and strategy must be carried out carefully until PT Berau Coal's mining permit expires in 2025. Financial assessment must accommodate the risks and uncertainties that exist to overcome the weaknesses of the DCF method. The monte carlo symulation method serves as an alternative for creating dynamic quantitative models for mining projects. In this method, the discounted risk factor is applied directly to variables of uncertain sources, such as coal prices, to improve accuracy. Therefore, evaluating long-term mine planning at PT Berau Coal using scenario analysis and Monte Carlo simulation is useful for making better decisions in production, investment and resource allocation schemes. With the results of a financial evaluation of NPV DCF 38mio USD, NPV Monte Carlo 40mio USD, IRR 51%, PI 4.12, and PBP 2.28 years PT Berau Coal will consider and make a decision whether to continue the project considering several risks or cancel the investment and not continue mining in Pit CACD.

Does natural gas volatility affect Bitcoin volatility? Evidence from the HAR-RV model

ABSTRACT While volatility spillover is a vital research area in financial economics (due to its importance for risk valuation and portfolio diversification strategies), the volatility linkage between Bitcoin and electricity/energy markets has not received adequate attention. As the Bitcoin mining cost comes mainly from electricity (which is highly dependent on natural gas), we hypothesize that natural gas is a non-trivial Bitcoin price volatility driver and aim to test if this is the case. Specifically, we employ a widely used model called the HAR-RV model to assess volatility spillover across Bitcoin and natural gas using high-frequency data. We find a spillover effect from natural gas to Bitcoin, and the positive (negative) component of natural gas volatility stabilizes (destabilizes) Bitcoin volatility. The spillover effect is further examined and confirmed using an out-of-sample approach.

Enrichment of sludge dump coal by spiral separation

The purpose of the presented research is to study the possibility of obtaining an additional coal product and ironcontaining concentrate from the sludge of a coal hydraulic dump. The research involved the study of the material composition of the initial sludge and technological tests. Material composition was examined using chemical, granulometric and mineralogical analyzes, the technological tests were conducted according to the gravitational-magnetic enrichment scheme. A spiral separator was used as the main enrichment equipment. Finishing operation was performed by the method of wet magnetic separation. Having studied the material composition, we determined that the initial sludge of the hydraulic dump is represented by 44.7 % of black coal and 43.32 % of brown coal. The bulk of hard coal is distributed in the size range of -2+0.25 mm and makes 51.15 %, brown coal is distributed in the size range of -2+0.25 mm in the amount of 13.32 %. The material is predominantly represented by a particle size of less than 0.25 mm with a high ash content in it. A coal concentrate with the ash content of 14.4 % was obtained as a result of technological tests. This product corresponds to the brand LFF (long-flaming fine). An iron-containing concentrate with the iron mass fraction of 64.7 % can be used in the metallurgical industry or in heavy-medium separation for coal enrichment. The study illustrates the possibility of obtaining high-quality secondary raw materials without additional mining costs using environmentally friendly technology.

ФРИКЦІЙНІ ЯВИЩА У ВУГІЛЬНИХ ШАХТАХ: ПРИЧИНИ, НАСЛІДКИ ТА ВПЛИВ НА ГАЗОДИНАМІЧНІ ЯВИЩА

Coal mines are objects of increased danger, since dynamic, gas-dynamic and thermal phenomena occur in them. These phenomena lead to violations of the operating regime, the failure of mining equipment, the death of miners, an increase in the cost of coal mining and other consequences. The purpose of the article is to present the results of studies of the conditions for the formation of thermal effects in coal mines and the reasons for their occurrence, which has both scientific and applied relevance. The conducted studies made it clear that sparking can occur under the influence of both man-made and natural factors. Friction phenomena leading to thermodynamic effects have been recorded in many mines and countries of the world. The main part of explosions and fires of methane occurs during frictional sparking of rocks containing sulfides. The latter produce sparks of a sufficiently high temperature, which can lead to the ignition of combustible gases, as well as the release of hydrogen sulfide, which has a low ignition temperature. In world practice, cases of ignition of combustible materials during the landing of the roof in the absence of coal have been described. British researchers concluded that the methane-air mixture can be ignited by a spark generated by the friction of sandstone against sandstone or mudstone against sandstone. According to the literature data, the ignition of combustible materials and coals can occur as a result of: emissions and explosions, rock collapse during landing, when a spark discharge occurs in quartz during a tribo- or piezoelectric effect; the presence of sulfides in coals or rocks, pyroelectric effect; electrification of coals. At the micro level, in quartz grains of sandstones, the formation of static charges by dislocations, which are decorated with dust, has been established. A particularly strong effect can occur if, in addition to methane, carbon monoxide, hydrogen, hydrogen sulfide, and acetylene are present in the air. An increase in sparking during frictional friction of quartz in the presence of coal dust has been established. The presence of gas inclusions in sandstone minerals during shear deformations leads to the appearance of additional concentrations of hydrocarbons. As a result of contact of such a mixture with a heated area, a short-term small flash occurs, which is a spark.

ПРОЄКТУВАННЯ ПРОЦЕСІВ ОСВОЄННЯ РОДОВИЩ КОРИСНИХ КОПАЛИН НА ОСНОВІ ДОСЛІДЖЕННЯ ЗМІНИ СТАНУ ЗАПАСІВ

Purpose. Develop a new approach to the design of processes that accompany the development of mineral deposits. This will allow considering the multiplicity and different degree of influence of the parameters on the overall efficiency. Methods. A decomposition approach is applied to optimize multi-parameter processes of mining production. Network models and optimization algorithms on networks and graphs for finding the optimal strategy for the development of mineral deposits. A model of the study of changes in the state of reserves for the design of technological processes that accompany the extraction of minerals. Results. The method of optimization of the parameters of the development of mineral deposits was proposed based on the presentation of alternative options of technological processes in the form of a network model. Depending on the type of mineral, as well as the expediency of mining waste enrichment, two design strategies are proposed. If it is advisable to enrich the waste, then it is necessary to maximize the value of a ton of rock mass. If it is impractical to enrich mining waste, it is necessary to minimize the costs of mining a ton of mineral. To increase the efficiency of exploitation of ore deposits of minerals, it is proposed to use mining waste as a component mixture for paving the produced space. The volume of work on the establishment of the developed space is determined on the basis of marginal analysis. In order to increase the efficiency of the operation of coal deposits, it is proposed to minimize the amount of waste that comes to the surface. Alternative options for the exploitation of the coal deposit were considered and two strategies were proposed: one consists in the minimization of waste, which involves selective extraction and laying of the produced space, and the other strategy consists in the maximization of the extraction of associated minerals, which involves combine extraction, separation of cargo flows, additional enrichment of waste. Scientific novelty. Scientific novelty consists in the development of a new approach, as well as in the creation of models for the development of mineral deposits. The algorithm for designing the process of development of mineral deposits is given. If it is impractical to enrich mining waste, then we apply the programming of the alternative graph to the minimum, which will minimize the cost of extracting 1 ton of useful mineral, in the other case, the programming of the alternative graph to the maximum, which will allow to maximize the cost of 1 ton of mining mass. Fulfillment of these conditions will increase the efficiency of production and reduce the man-made load on the environment. Practical implication. It consists in the creation of a package of application programs for designing the processes of development of mineral deposits. Keywords: strategy, production waste, design, ecology, technological scheme, graph, software.

James E. Talmage and the Selenite Crystals

James E. Talmage and the Selenite Crystals

ПОВЫШЕНИЕ ЭФФЕКТИВНОСТИ ТЕХНИЧЕСКОЙ ЭКСПЛУАТАЦИИ КАРЬЕРНОГО АВТОМОБИЛЬНОГО ТРАНСПОРТА

The paper considers the main measures aimed at improving the efficiency of technical operation of quarry road transport. It is established that in order to increase the engine life and reduce the time and material costs of mining and processing plants, it is necessary to use restored parts for repair, have one backup engine in the working capital of the enterprise for repair, use the developed structure of repair with effective frequency, volume and content of work, as well as apply a non-brake run-in of the engine after repair.

Adaptive mining difficulty for blockchain to resist selfish mining attack

Aim: A blockchain provides data consistency and builds a fair mining environment for a network by using a consensus mechanism such as proof of work (PoW) and proof of stake. However, selfish mining is a well-known mining attack. It can reduce the fairness and destabilize the network, especially for a PoW-based blockchain. Therefore, in this paper, we propose a new approach, named the adaptive mining difficulty adjustment protocol, which can deter a selfish attack. Methods: We propose using the unit profit as an improved version of the relative revenue, because it is more flexible for calculating the miners’ profits in different periods and can be used to analyze repeated mining games. Based on the unit profit, we propose using the adaptive mining-difficulty adjustment protocol to reduce an attacker’s profit. Our protocol evaluates the effective hash power in a network more accurately and corrects the mining difficulty. Moreover, we introduce the discount factor and model the long-term profit to analyze the impact of a miner’s patience on its future profit. Results: We used an open-source simulator to simulate the competition between a selfish miner and an honest miner and determined their profits under different protocols. Our experimental results show that our protocol can effectively raise the attack threshold, but it reduces the total network profit if the attacker still attacks. However, the long-term profit model shows that a more patient attacker needs to invest more hash power and pay increased mining costs to maintain its attack. Conclusion: We conclude that, under our protocol, selfish attackers will tend to become honest miners if their hash power does not exceed the threshold, which means that our protocol can effectively deter selfish attacks and some variants of selfish attacks. Briefly, our protocol can correct the mining difficulty and leads to a more stable and fairer mining environment for a PoW-based blockchain.

Environmental Consequences of Mining Bitcoin: The Carbon Emission in China

In recent years, as cryptocurrency has been recognized by more people and the value of the cryptocurrency has increased, many people make money through mining. It leads to mining becoming popular but also creates serious environmental problems. Mining bitcoin will consume much electricity and thus emits more greenhouse gases such as carbon dioxide, which has caused worldwide environmental issues. This paper will focus on figuring out that mining bitcoin will cause how much carbon emission damage in China during these years. The result of this research will provide the change in carbon emission with time and the prediction of the carbon emission trend caused by bitcoin mining in the future. This result of the article aims to focus the society and the government's attention on the damage mining bitcoin does to the environment and also provide suggestions on the measures the governments should take to reduce the unessential energy cost of bitcoin mining.

Optimal mining in proof-of-work blockchain protocols

This paper examines the economic mechanism of cryptocurrency mining. By presenting a profit function, a maximization equilibrium is obtained. The model provides a formal approach to the demand for hashing power as a function of revenues, mining costs and the number of miners. We consider how the equilibrium is affected by passive miners. We use these results to introduce a formulation of the price elasticity of the demand for hashing power with respect to the cost of energy. The model is simulated using Reinforcement Learning algorithms that arrive to similar equilibrium results. The article concludes with implications of the model for policymaking.

Haul road condition impact on tire life of mining dump truck

Purpose. Off-road tires (OTR) for mining and earthmoving applications which are specially developed for extreme mine site conditions can take 1020% of transportation costs. Up to 15% of OTR content is natural rubber produced from a rubber tree known as hevea brasiliensis. A significant number of OTR fail before the target life built in by tire manufacturers. This has certain negative impacts on the environment and wildlife due to deforestation effect. Thus, the purpose of the work is to increase the durability or, in the terminology of the operators, the mileage of the OTR. Methodology. The current study represents analyses of new modern digital technology for monitoring the mining haul road condition within a site study on Bogatyr Komir coal mine in North Kazakhstan. The influence of operating conditions was controlled, i.e. road quality, temperature conditions, tire pressure, and other parameters on tire life. Findings. The results show the effectiveness of digital technologies and the possibility of extending the life of tires by following the recommendations of the system in a timely manner. As a result of the analysis of temperature regimes and pressure in tires, especially in summer conditions, recommendations for rational operating conditions were determined, which makes it possible to increase the durability of tires. Originality. Modern operational digital methodology for monitoring open pit mines road condition defines ton kilometer per hour (TKPH) indicator per every trip, which provides on-time information for road design and maintenance. Practical value. Growing worldwide demand is driving the development of the mining industry. In the future, more and more fields with a low content of produced raw materials will be put into operation. The development of deposits with a low content of a useful product means that more rock mass must be moved in order for these developments to be profitable. Transportation costs in low-grade mines can be as high as 70% of mining costs due to more haul trucks and longer roads that need to be commissioned. Thus, an increase in the durability of OTR can give a great economic effect not only in the conditions of the Bogatyr Komir quarry under consideration but also in other mining and processing plants.

Research into Impact of Leaving Waste Rocks in the Mined-Out Space on the Geomechanical State of the Rock Mass Surrounding the Longwall Face

Backfilling technology is not always used by mining enterprises, which is conditioned by technological and economic factors, such as the need for high mining rates and costs for the technological processes of transporting backfill materials from the daylight surface to the mined-out space. This concerns the underground mining of hard coal, which is a strategic energy resource, in the mines of Ukraine. This paper aims to study the effect of leaving the waste bottom rocks in the mined-out space of the longwall face without their drawing to the earth’s surface on the geomechanical state of the rocks surrounding the longwall face. The geomechanical assessment of the stress state of the rock mass surrounding the longwall face, when leaving the waste rocks from the seam bottom rocks in the mined-out space, is performed by the finite element method using the Ansys software package. A geomechanical model has been developed and substantiated, which adequately reflects the mining-geological conditions for seam mining within the extraction site, the actual structure and properties of the coal-bearing rock stratum, the parameters of the longwall face and the modified powered support for the processes of leaving the rocks in the mined-out space. The values and patterns have been determined of the decrease in the stress intensity concentrations in the coal-bearing roof mass in the frontal bearing pressure zone and destressing zone with an increase in the ratio of the rock pack thickness to the extracting seam thickness. The relative indicators of the load on the powered support section and the lowering of its roof have been determined by the ratio of the thickness of the rock pack formed in the mined-out space to the extracting seam thickness. The proposed mining method is of significant commercial and research interest for owners of coal mines developing thin coal seams because environmental costs for placing waste on the surface are reduced, and the energy potential of coal is increased due to the separation of waste rocks from coal in underground conditions. The need for a cycle of beneficiation of mined mass is eliminated and the geomechanical conditions of coal mining processes are improved.

Application of High Precision Mining for Optimising Load and Haul Operations at Kansanshi Mine, Zambia

Mining of copper and gold at Kansanshi is done in the Main and North West pits using hydraulic excavators and a mining fleet of haul trucks. In the recent past, there has been reduced truck deployment, increased truck and shovel waiting time, reduced production and reduced grade/quality of ore delivered to crushers. Therefore, there is need to improve productivity and optimise operations in mining, loading and hauling. This paper focuses on the use of High Precision Mining (HPM) through use of Wenco’s dispatching algorithm to achieve the best utilisation of all mining equipment and maximise production. The study involved establishing the precise bucket positioning, production rates, cycle times and monitoring the material type and quality /grade of ore delivered to the crushers. This was done by using BenchManager which relies on the motion of the Global positioning System (GPS) antenna scribing an arc as the excavator is rotated to determine the equipment’s centre of rotation by placing the bucket with the teeth flat on the ground (anywhere) and taking the rover and measuring left and right tooth on the outside of the teeth and taking note of the coordinates, first eastings then northings and lastly the elevation. With the tolerance of X=0.5m, Y=0.5m and Z=0.5m, it was noted that the events of a bucket mining out of the assigned polygon were reduced to about 50cm in distance from 34% to 15% and from 10% to 8% in terms of mismatches. The use of precision mining has led to reduced mining cost of about 10.3$/BCM, improved fleet/production reporting, high grade of the material delivered to the crushers of about 75% from the previous 65%. These results indicate that there is a strong business case for implementation of a Wenco fleet monitoring and dispatch system at the mine

Alkaliphiles for comprehensive utilization of red mud (bauxite residue)—an alkaline waste from the alumina refinery

The mining industry has powered the human endeavor to make life more innovative, flexible, and comfortable. However, it has also led to concerns due to the increasing amount of mining and associated industrial waste. Special attention is highly desired for its proper management and safe disposal in the environment. The problem has only augmented with the increase in the mining costs because of the investments needed for ecological remediation after the mining operation. It is pertinent that the targeted technologies need to be developed to utilize mining and associated industrial waste as a secondary resource to ensure sustainable mining operations. Every perceived waste is a valuable resource that is needed to be utilized to create additional value. In this review, the case of alkaline bauxite residue (red mud)-alumina refinery waste has been discussed at length. The highlight of the proposed work is to understand the importance of alkaliphile-assisted biomining-a sustainable alternative to conventional metal recovery processes. Along with the recovery of metals, pH reduction of red mud is possible through biomining, which ultimately paves the way for its complete utilization. The unique adaptation strategies of alkaliphiles make them more suitable for biomining of red mud through bioleaching, biosorption, and bioaccumulation, which have been discussed here. Furthermore, we have focused on the potential of the indigenous microflora of red mud for metal recovery in addition to its neutralization. The study of indigenous alkaliphiles from red mud, including its isolation and propagation, is crucial for the industrial-scale application of alkaliphile-based technology and has been emphasized.

Influence of High Sulfate Mine Water on Spontaneous Combustion of Coal.

Mine water cannot be discharged until it has been treated, which increases the cost of mining and causes environmental damage. This paper attempted to use sulfate mine water as a flame retardant material for the treatment of coal spontaneous combustion (CSC) in underground mines. The temperature-programed experimental device and gas chromatograph were used to simulate the low-temperature oxidation process of coal. Infrared spectroscopy was used to study the influence and inhibition mechanism of mine water and chloride inhibitor on active functional groups. It was found that although the sulfate mine water inhibited the formation of -OH, it accelerated the cleavage of the aromatic ring. The thermogravimetric experiment was used to analyze the ignition temperature and activation energy of different coal samples. It was found that mine water had an obvious effect on inhibiting CSC in the combustion stage, which could increase the oxidation temperature of coal.

Aggregate and disaggregate impact of natural resources on economic performance: Role of green growth and human capital

A curse or blessing, natural resources remains a dilemma with diverse findings for both developed and developing economies. However, the disaggregated and aggregated impacts of natural resources have not yet been unearthed for high-income economies, i.e., the G-7 economies. This study is hence aimed to explore the aggregated and disaggregated impacts of natural resources on economic growth and the controlling role of carbon emissions, human capital, and green growth from 1990 to 2020. To obtain the coefficients of the selected regressors, the novel Method of Moments Quantile Regression (MMQR) approach is employed. From the empirical estimations, it is concluded that the availability of aggregated and disaggregated natural resource is negatively intertwined with economic development among the G-7 nations, thereby validating the existence of the “resource curse” hypothesis at both aggregated and disaggregated levels. This outcome is consequential and calls for immediate attention from the high authorities in the G-7 region. The member nations should work cooperatively to establish a stable regional market that can absorb the price volatility of natural resources and control the demand and supply mismatch of energy and related natural resources, which will help to attain steady-state economic growth. Additionally, the mining cost and mining-induced environmental costs need to be minimized through technological forwardness and scientific mining. The findings also unveil that green growth reduces economic development among the G-7 nations. This is justified, given that green growth requires more dependence on clean energy sources, which means less extraction and consumption of fossil fuels. Moreover, human capital development and CO2 emissions are boon for economic amelioration among the panel nations; however, CO2 emissions-induced development is highly discouraged considering the G-7 nation's green growth directory. However, it is speculated that the green growth agenda may exacerbate the region's resource curse dilemma. Therefore, the G-7 nations should cautiously estimate the trade-offs between green growth and a natural resource-induced curse.

A Novel Design Concept of Cemented Paste Backfill (CPB) Materials: Biobjective Optimization Approach by Applying an Evolved Random Forest Model.

For cemented paste backfill (CPB), uniaxial compressive strength (UCS) is the key to ensuring the safety of stope construction, and its cost is an important part of the mining cost. However, there are a lack of design methods based on UCS and cost optimization. To address such issues, this study proposes a biobjective optimization approach by applying a novel evolved random forest (RF) model. First, the evolved RF model, based on the beetle search algorithm (BAS), was constructed to predict the UCS of CPB. The consistency between the predicted value and the actual value is high, which proves that the hybrid machine learning model has a good effect on the prediction of the UCS of CPB. Then, considering the linear relationship between the costs and the components of CPB, a mathematical model of the cost is constructed. Finally, based on the weighted sum method, the biobjective optimization process of the UCS and cost of CPB is conducted; the Pareto front optimal solutions of UCS and the cost of CPB can be obtained by the sort of solution set. When the UCS or the cost of CPB is constant, the Pareto front optimal solutions can always have a lower cost or a higher UCS compared with the actual dataset, which proves that the biobjective optimization approach has a good effect.

Socioeconomic cost of dredge boat gold mining in the Tapajós basin, eastern Amazon

With the rapid expansion of artisanal small-scale gold mining (ASGM) in the Brazilian Amazon, an increasing number of studies have attempted to estimate the impacts and socio-environmental costs of ASGM using economic valuation methods. However, most studies focused on alluvial gold mining and few examined dredge boat mining, leading to an under-estimation of the overall impact of ASGM in some regions. The objective of the present study was to develop a methodology for assessing the socio-environmental costs of dredge boat mining in the Tapajós watershed. We developed a method linking the type of gold mining, type of pump, motor power required, time spent in exploration, and mercury use with the average socioeconomic cost. We identified 13 boats in the Tapajós basin in 2020 using satellite images. The total socioeconomic cost of dredge boat mining was US $6.4 million in 2020 (i.e., US $142,556 per kilogram of gold or US $588,887 per ferry). The estimated dredging impact cost may reach US $14.7 million for an optimistic scenario, which would reach US $443.9 million when considering accumulated impact over 30 years. These findings can contribute to a more accurate economic valuation of illegal dredge boat mining, providing valuable information for estimating compensation fines and planning law enforcement investments to prevent illegal ASGM.

Latin American Extractivism: Dependency, Resource Nationalism, and Resistance in Broad Perspective

Latin American Extractivism: Dependency, Resource Nationalism, and Resistance in Broad Perspective

Influence of backfilling rate on the stability of the “backfilling body-immediate roof” cooperative bearing structure

To reduce the cost of backfilling coal mining and utilize the underground space of coal mines, a new backfilling mining method with low backfilling rate called constructional backfilling coal mining (CBCM) is proposed. The “backfilling body-immediate roof” cooperative bearing structure of CBCM is analyzed by establishing the model of the medium thick plate on an elastic foundation. The influence of the backfilling rate on the stability of overlying strata is analyzed by the numerical simulation experiment. The control effect of CBCM is verified by a physic similar simulation test. The economic benefit of CBCM is analyzed. The conclusions are: the deformation characteristics of the immediate roof and critical backfilling spacing in CBCM can be analyzed based on the Hu Haichang’s theory. Exerting the bearing capacity of the immediate roof is beneficial to the stability of the overlying strata. The CBCM has a good control effect on the overburden in Xinyang Mine when the backfilling rate is lower than 25%. The backfilling cost of per ton coal is 37.39 yuan/t when the backfilling rate is 13.7%, with a decrease rate of 56.63% than the full-filling. The research results can provide theoretical support for the application of CBCM in coal mining.