Mill Work Research Articles

Exploring the Link between HY Wet Ball Mill Work Index and Grinding Energy Consumption

Exploring the Link between HY Wet Ball Mill Work Index and Grinding Energy Consumption

The Influence Of Work Environment And Motivation On Employee Spirit At Pt Perkebunan Nusantara IV, Gunung Meliau Palm Oil Mill Work Unit

This study aims to identify and analyze the influence of the Work Environment and Motivation on the Work Spirit of employees at PT Perkebunan Nusantara IV, Gunung Meliau Palm Oil Mill Work Unit. The population in this study consists of 125 individuals, using a saturated sampling technique. Data collection techniques in this study include interviews and questionnaires. The analytical tools used in this research are instrument tests, classical assumption tests, multiple linear regression analysis, correlation coefficients, determination coefficients, F-tests, and T-tests. The results of the study show that the work environment and motivation affect work spirit both simultaneously and partially. Therefore, to enhance work spirit, both the work environment and motivation must be well managed

Climate justice and global development: outlining a new framework from the work of Achille Mbembe and Charles Mills

ABSTRACT As currently understood and practiced, global development and climate justice appear irreconcilable. In fact, global development has been and remains a key driver of climate inequalities. We hold that this is not an accident, but instead is a result of global development being established within worldwide systems of oppression. We define global development as setting the goals for, and the processes for achieving, what constitutes a good life for all communities, and taking the steps needed to reach those goals. This article provides an outline of how the theories of two moral and political philosophers – Achille Mbembe and Charles Mills – point us in the direction of an ethical framework for the relationship of humans to each other and to the natural world. We examine two contexts that should motivate development practitioners to move from the current development regime toward the direction of a transformational ethical framework built off the work of these philosophers: (i) the perpetual failure of global development practice to foster a humane approach to migration; and (ii) the inability of global development solutions, like SDGs and leapfrogging, to stray from the very problems they are intended to address.

Could commodities themselves speak? An introduction to the agnotology of the spectacle

This article introduces the ‘agnotology of spectacle'. While agnotology is a relatively recent term used to describe the production and use of ignorance, we argue that Debord's Comments on the Society of the Spectacle (1992) is an early attempt to outline a global field of disinformation and secrecy. For Debord, such secrecy is required to maintain the political and moral authority of what he defined as ‘spectacle', namely the images used by states and corporations to mediate relations of power with consumers and citizens. We consider how the spectacle creates fields of disinformation and secrecy to maintain its political and moral authority by examining notes in commodities that purport to be calls for help from coerced labourers in China. These notes allow us to assess the uncanny experience of consuming goods manufactured across global supply chains which may well comprise of serious labour exploitation. However, these sources also demand a more expansive agnotology than that provided by Debord: one that engages with labour processes, contracts and race. We therefore develop Debord's ideas by examining the work of Mills and Benaji. Finally, drawing on Brecht's concept of the 'estrangement effect', we discuss how exploited workers can co-opt the aesthetics of the uncanny to articulate their subject position within a global agnotological field.

Extensive Validation of a New Rock Breakage Test

Comminution is the most power-demanding stage, and the lack of geometallurgical testing, often for financial reasons, may result in an inefficient operation. The Geopyörä rock breakage test was developed with the objective of making mineral variability data more accessible by providing both standard comminution parameters and rock mechanical properties at low cost and with a modest sample size, allowing a larger number of samples to be tested to reduce uncertainties and assure productivity. The objective of this work is to present the results of an extensive validation of this new rock breakage method against two of the main tests currently in use, namely the SMC and Bond ball mill work index tests. More than 100 samples have been tested and the results compared, showing that the new method can accurately estimate the parameters of the traditional tests. This confirms that the new test is a reliable tool for performing comminution and geometallurgical tests.

Research on the Online Monitoring of the Service Status of Hot-Rolling Mill Work Rolls and Online Decision-Making Method for Active Remanufacturing

Research on the Online Monitoring of the Service Status of Hot-Rolling Mill Work Rolls and Online Decision-Making Method for Active Remanufacturing

Cost and statistical efficiency of posture assessment by inclinometry and observation, exemplified by paper mill work.

Postures at work are paramount in ergonomics. They can be determined using observation and inclinometry in a variety of measurement scenarios that may differ both in costs associated with collecting and processing data, and in efficiency, i.e. the precision of the eventual outcome. The trade-off between cost and efficiency has rarely been addressed in research despite the obvious interest of obtaining precise data at low costs. Median trunk and upper arm inclination were determined for full shifts in 28 paper mill workers using both observation and inclinometry. Costs were estimated using comprehensive cost equations; and efficiency, i.e. the inverted standard deviation of the group mean, was assessed on basis of exposure variance components. Cost and efficiency were estimated in simulations of six sampling scenarios: two for inclinometry (sampling from one or three shifts) and four for observation (one or three observers rating one or three shifts). Each of the six scenarios was evaluated for 1 through 50 workers. Cost-efficiency relationships between the scenarios were intricate. As an example, inclinometry was always more cost-efficient than observation for trunk inclination, except for observation strategies involving only few workers; while for arm inclination, observation by three observers of one shift per worker outperformed inclinometry on three shifts up to a budget of €20000, after which inclinometry prevailed. At a budget of €10000, the best sampling scenario for arm inclination was 2.5 times more efficient than the worst. Arm inclination could be determined with better cost-efficiency than trunk inclination. Our study illustrates that the cost-efficiency of different posture measurement strategies can be assessed and compared using easily accessible diagrams. While the numeric examples in our study are specific to the investigated occupation, exposure variables, and sampling logistics, we believe that inclinometry will, in general, outperform observation. In any specific case, we recommend a thorough analysis, using the comparison procedure proposed in the present study, of feasible strategies for obtaining data, in order to arrive at an informed decision support.

Development of a simplified test for the determination of the Bond Ball Mill Work Index using a modified Hardgrove test

Grinding ores in conventional ball mills demands high energy consumption, resulting in relatively high operating costs in a typical mineral processing industrial plant. Whether in the initial stages of a mining project or during its operation, conducting tests to determine the processing circuit’s energy consumption throughout the life of mine is necessary in order to reduce such high operating costs. Traditional tests used to determine the energy consumption in grinding, like the Bond Ball Mill test, are relatively time-consuming and require significant amounts of sample, e.g., 8–10 kg, which is not always available in the initial stages of a mineral project or geometallurgical studies. Several authors have developed simplified tests to predict ball mill’s energy consumption, typically using the Bond Ball Mill Work Index (BBMWI) as a reference. One option requiring less mass is the Hardgrove mill, traditionally used in the laboratory to determine the energy required to grind coal in roller mills. This test requires 50 g of sample, and the result is based on the amount of fines at the end of grinding to a fixed time. The present study used a modified Hardgrove test to predict the BBMWI. This test involves the measurement of the torque, uses a fixed sample volume with different particle feed sizes from the Hardgrove standard, and determines the specific energy related to the percentage of product passing through the closing size screen of the Bond test, defined as the size specific energy. The results indicated that for a set of 13 samples with the 150 µm closing screen, the average error associated with the predicted BBMWI is within ±2.3%. Further results indicate an error of ±3.1% for 20 samples with the 106 µm closing screen. The correlations presented here are proposed to be validated and/or adjusted for different ores and mines. The proposed test is thus suitable for geometallurgical studies and other applications where relatively small samples are available. In addition, this is a low-cost test, has a quick turn-around time, it is simple to conduct and does not require the handling of heavy loads by operators.

Grindability characterization and work index determination of alluvial ferro-columbite deposits for efficient mineral processing

This study emphasizes on the physicochemical and grindability characteristics and work index of an alluvial formed silica dominated ferro-columbite mineral from Rayfield-Jos minefields in Plateau state, Nigeria. Investigations were also carried out in order to determine the mineralogy of the mineral deposits and most essentially the actual energy consumed during comminution and milling of the mineral so as to achieve the liberation size prior to high efficient mineral processing or beneficiation and the extraction of value metals. The distribution of the mineral particles as well as their sizes was determined, with a mineral liberation size fraction range essentially established as -150+90 µm particle sizes. Mass percentage of each size fraction obtained from PSD analysis conducted before and after comminution was also determined, obtaining 80% passing for both the mineral feeds and comminuted products. Berry and Bruce modified Bond’s work index was therefore obtained, and was determined to be within the range of 2.0414 to 2.5667 kWh/ton. Hence, the energy consumed or required to comminute or grind the Fe-columbite mineral to 80% passing is expected to fall within the range of 0.3613 to 0.4543 kWh. Thus, it could be said that a low milling work index as well as moderately low energy is required for comminution and this can be attributed to the mineralogy, mineral source and alluvial formation of the mineral reserve. Therefore, the grindability/PSD result of the mineral sample indicates that its mineralogy is considered a class of moderately soft mineral type in terms of texture with easy grindability.

Estimation methodology for Bond ball mill work index experiment output via mathematical modeling

The Frederick C. Bond has several grinding indices (ball, rod, abrasion), one of which has been a significant guide for ball mills. The Bond ball mill work index is an expression of the material’s resistance to ground and a measure of the grinding efficiency. The test is a standardized methodology that ends when a circulating load of 250% is obtained. In this paper, a new method based on the Population Balance Model (PBM) is proposed and validated to estimate the results of the Bond ball mill work index test (WiB). The model presented in this study combines the first cycle of the Work Index test (at 250% circulating load) with the PBM. Impure limestone, fluorite, chalcopyrite, and hematite ores were used to run both tests with a good confidence level (SSE less than 0.4 in all samples tested). As stated, based on the methodology the operational parameters for grinding (charge level, ball size distribution, and critical speed) were kept constant. The methodology developed showed great simplicity and potential applicability to a wide range of minerals by carrying out only one grinding test and numerical iteration to obtain a 250% circulating load.

Coding in rural Balinese non-formal education: social reproduction theory and liberal empowerment

ABSTRACT Following the work of Tamatea and Pramitasari in the Bali Coding Class (2018), we ask if liberal empowerment can sit alongside Bourdieu’s social reproduction theory in framing a non-formal education coding class for rural Balinese youth. While a review of critical theory informed literature suggests not, we appropriate the work of Mills to read data obtained from coding class students, teachers, and industry representatives to suggest otherwise. Focusing upon four ‘problematics’ identified in the ‘critical’ literature, we argue that Mills’ non-ideal deracialised liberalism provide the conceptual space for working with liberal empowerment and social reproduction theory contiguously.

A Study of Magnetic Mill Productivity

The paper explores the characteristic indicators of the operation of a magnetic mill. A magnetic mill is a device designed for grinding or mixing substances by interaction with ferromagnetic working elements moving in a rotating magnetic field. The study established the main factors influencing force interaction between the components of such a system. An analysis of the magnetic field inside the working zone of the mill was conducted and the method of calculating the quantitative indicators of this interaction was found. The method responds to changes in the size of these elements, their position in the mill working area and changes in the intensity of the magnetic field. A mathematical model was developed. The model is used for calculating the trajectories of movement of the ferromagnetic elements that are placed in a rotating magnetic field and are confined by space of the working zone of the mill. Indicators directly related to the productivity of the grinding/mixing process were determined following an analysis of the simulation results. Based on comparison of the results obtained by calculation and experimental methods, it was proven that the proposed method is suitable for evaluating the productivity of the grinding/mixing process in a real technological system containing a magnetic mill.

The expendables: Bioarchaeological evidence for pauper apprentices in 19th century England and the health consequences of child labour.

Child labour is the most common form of child abuse in the world today, with almost half of child workers employed in hazardous industries. The large-scale employment of children during the rapid industrialisation of the late 18th and early 19th centuries in England is well documented. During this period, the removal of pauper children from workhouses in cities to work as apprentices in rural mills in the North of England was commonplace. Whilst the experiences of some of these children have been recorded historically, this study provides the first direct evidence of their lives through bioarchaeological analysis. The excavation of a rural churchyard cemetery in the village of Fewston, North Yorkshire, yielded the skeletal remains of 154 individuals, including an unusually large proportion of children aged between 8 to 20 years. A multi-method approach was undertaken, including osteological and palaeopathological examination, stable isotope and amelogenin peptide analysis. The bioarchaeological results were integrated with historical data regarding a local textile mill in operation during the 18th-19th centuries. The results for the children were compared to those obtained from contemporaneous individuals of known identity (from coffin plates) of comparable date. Most of the children exhibited distinctive 'non-local' isotope signatures and a diet low in animal protein when compared to the named local individuals. These children also showed severe growth delays and pathological lesions indicative of early life adversity, as well as respiratory disease, which is a known occupational hazard of mill work. This study has provided unique insights into the harrowing lives of these children; born into poverty and forced to work long hours in dangerous conditions. This analysis provides a stark testimony of the impacts of industrial labour on the health, growth and mortality risk of children, with implications for the present as well as our understanding of the past.

Leaching Test Protocols to Evaluate Contaminant Response of Nano-Calcium Silicate–Treated Tropical Soils

The current study deals with the interaction of toxic metals with soils by conducting a series of leaching tests on four kaolinitic soils procured from locations with varying pollution levels, such as a pristine location, vicinity of steel mill works, battery works unit, and an abandoned municipal waste dump site. The procured soils were spiked with 3,000 mg/kg of toxic metals, lead (Pb), and nickel (Ni) to understand the contaminant transport. An innovative amendment, such as synthesized nano-calcium silicate (NCS), was also mixed with the soils for toxic metal immobilization. Leaching tests. such as the toxicity characteristic leaching procedure (TCLP), extended TCLP, and caged TCLP, were conducted on soil samples. These tests were successful in predicting the interactive behavior of the composite mix containing soil, NCS, and toxic metals, comprehensively. The vulnerability of soils based on TCLP can be expressed in the order of Soil C > Soil D > Soil B > Soil A. These results were concurrent with extended TCLP, wherein the response of these composites at various pH levels was presented. Caged TCLP quantified the leaching rate for different mixtures, and it was found that the leaching rate for virgin soils reduced from 1.3 to 0.075 cm/yr after the NCS amendment. The addition of NCS resulted in the agglomeration and aggregation of soil particles. This increased the density and reduced the void spaces of the soil–nano mix, thereby encapsulating the toxic metals permanently within its interstices. The highest attenuation was observed for Pb2+ compared with Ni2+ for all the mixtures considered. Thus, leaching tests can be considered a prospective short-term technique for monitoring polluted soil media compared with tedious and time-dependent column studies.

The Telling Case of Doctor Bhagat Singh Thind: Indian Nationalist, Citizen, and Spiritual Teacher

On February 19, 1923, the U.S. Supreme Court ruled in United States v. Thind that Indians were not White and therefore not eligible for citizenship, a decision that stood for decades. Bhagat Singh Thind, an émigré from Punjab, India, then working in Linnton, Oregon was the man behind this precedent-setting case who built a life despite its far-reaching implications. Historian Ogden considers the arc of Thind’s life — mill worker, Ghadar activist, court litigant and Hollywood-based spiritual teacher — as a synthetic whole, with an emphasis on the global political realities, repression, and personal beliefs shaping his transformations. Thind’s multi-dimensional life provides a telling glimpse into an enduring American racial lineage.

Harriet Taylor and John Stuart Mill: Joint Creative Work in the Context of Private Life

The paper examines the life path and joint work of the English philosopher and economist John Stuart Mill (1806—1873) and his wife Harriet Taylor Mill (1807—1858). The facts of their biography and personal life were studied. The emphasis is on Harriet Taylor Mill's personality. The works of Mill, in which the influence of his wife is most clearly traced, are highlighted. The mechanism and features of their cooperation are shown. The author comes to the conclusion about the significant contribution of Harriet Taylor Mill to the works of John Stuart Mill, which allows us to talk about co-authorship.

A Museum for the Working Class

A Museum for the Working Class Joanne McNeil (bio) Hulking granite mills tower over the city of Fall River, some fifty miles south of Boston, as a lingering reminder of its industrial history. The weathered buildings were infamous for cruel labor conditions back when Fall River led the country in cloth production. The Fall River Museum of Contemporary Art has occupied the ground floor of one such mill, which still operates as a textiles manufacturer; with factory workers sewing upstairs, it's an unlikely place for an art museum. That's exactly why it's there. When I first visited in the fall of 2021, I parked next to the VFW hall beside FR MoCA and met with its founders, Brittni Ann Harvey and Harry Gould Harvey IV. The couple, who are in their early thirties, met as teenagers attending punk shows at that same VFW. Now their art is exhibited at prestigious galleries in New York, but they [End Page 15] hold ambivalent feelings about this prestige—and its associated social mobility. So they choose to live and work in Fall River, close to their families. The museum, which opened in 2020, exists in the hatchway the artists have carved out for themselves between the art world and home. Click for larger view View full resolution Fall River Study no. 1 by Isaiah Raines (courtesy of the artist) The Harveys might have named their non-collecting art nonprofit the "Fall River Gallery," but "museum" conveys institutional heft. Plus, the word hints at how, through their curation, they playfully subvert the traditional gatekeeping of the art world. Conceived as a "museum," FR MoCA reveals where typical art institutions fall short. Art museums, while ostensibly for the public, cater to the tastes of the wealthy, especially major donors with sway over programming and exhibited work. Operating at a small scale, FR MoCA, modestly funded with state art grants and support from local businesses—including the owner of a Portuguese food emporium across the [End Page 16] street—has a grassroots ethos. The project demonstrates that art is not exclusive to the sons and daughters of capital; artists and art workers come from communities like Fall River, too. And their work has context and history. Art has long existed here, the Harveys are quick to point out, citing as an example the mill worker and artist Robert Spear Dunning, who began the Fall River school of still-life painting. When I first visited the museum, there were photographs, boiler inspection tools, and souvenirs from the Fall River Line steamboat company on display in the hallway entrance. On loan from the maritime museum, the artifacts highlighted the disparities between the lives of the workers below the decks and the Gilded Age robber barons who would ride between their residences in Newport, Rhode Island, and Manhattan. Inside the exhibition space were vibrant yet quietly affecting works by the late artist Kathleen White, including her "Love Letters" series of abstract paintings in lusty colors and her Play-Doh-bright "Car" sculptures molded into faintly recognizable vehicular formations. She was closely associated with Nan Goldin and the downtown scene of the 1980s and '90s, but crucially, for the purpose of this exhibition, White grew up in Fall River. Her grandfather was a Fall River Line captain. Exhibited here, in her hometown, one could sense the origins of White's humble brilliance. "Rendering truth" is how Harry summarizes the FR MoCA mission, referencing a Lonnie Holley song title. To Harry, it means the "emancipation" and utopias that emerge when art is produced with integrity. It's a phrase he uses regularly as a synonym for art or artmaking, for the perspective an artist shares outside any sort of market logic or transaction. In a sense, the rendered truth of FR MoCA is the roots it seeks to establish. Exhibited artists either come from the area or their work engages with the city. The regional focus, in this plainly unfancy old mill town, means that labor is an evident through line. The historical context the Harveys develop as curators—displaying mill-worker still-life painters alongside contemporary artists—offers a place for working-class art without tokenizing or...

Simulation of mechanical wear of work rolls of a wide-strip hot rolling mill using machine learning methods

Modern methods of modeling a mechanical wear of hot rolling mill work rolls under industrial conditions are presented. The use of machine learning algorithms based on multidimensional linear regression, decision trees, and neural networks made it possible to describe more accurately the features of work roll wear depending on many technological factors. At the same time, the data set from the production database was subjected to additional classification for each technological parameter in a certain range. This classification approach significantly improved the quality of the output model for all major metrics. The input variables for training were the main technological factors measured in the finishing group of stands during the campaign of each work roll. The output parameters – wear curves on a roll grinder measured after roll changes. 93 input parameters were used to calculate each of the 300 output values of mechanical wear along the length of the roll barrel and to train machine learning algorithms. Roll wear forecasting models based on multivariate linear regression, random forest, gradient boosting and neural networks have been developed. A comparative analysis of the developed models with classical approaches for calculating the work roll mechanical wear showed that machine learning methods have a higher accuracy. An approach and recommendations for the introduction of new models to the automated process control system of hot strip rolling mills were proposed.The research was carried out within the framework of the program of strategic academic leadership of the Russian Federation "Priority 2030", aimed at supporting the development programs of educational institutions of higher education, the scientific project PRIOR/SN/NU/22/SP5/26 "Creation of innovative digital tools for the use of applied artificial intelligence and advanced statistical analysis of big data in technological processes of manufacture of metallurgical products", as well as within the framework of scientific and technical cooperation between JSC Vyksa Metallurgical Plant and Bauman MSTU.

Effectiveness of Structured Teaching Program on Knowledge regarding Occupational Health Hazards and its Prevention among Flour Mill Workers at selected rural area

Many people believe that work is worship, equally important is the place of work because the workplace has significant influence on individual’s health and is a primary site for the delivery of preventive health care. The present study intends to evaluate the effectiveness of Structured Teaching Programme on knowledge regarding occupational health hazards and its prevention among flour mill workers in selected rural area. The objectives are to assess the existing knowledge level on occupational health hazards and its prevention, to assess the effectiveness of structured teaching program on knowledge regarding occupational health hazards and its prevention. Quasi experimental, one group pre test and post test design was adopted. Evaluative approach with selected Flour mill in rural area. 60 Flour mill worker were selected by Random Sampling. The collected data was analyzed and interpreted by using descriptive and inferential statistics. The over all knowledge score obtained by the subject in the pre-test was 13.95 with standard deviation of 5.25 and in the post-test was 25.21 with standard deviation of the obtained “t” value for over all knowledge score 15.11 is found to be greater than the table value at the level of p<0.001. It revealed that there is an effectiveness of Structured teaching programme on occupational health hazards and its prevention among flour mill workers, hence the hypothesis H1 was accepted. The study proved that structured teaching programme on occupational health hazards and its prevention among flour mill workers was scientific, logical and coast effective strategy.

A new methodology to obtain a corrected Bond ball mill work index valid with non-standard feed size

The grindability of raw material is generally determined by Bond’s standard ball mill grindability test (developed by the Allis Chalmers company). The ball mill grindability test is used for describing ore hardness and it is so widespread that the Bond Work Index generated from the test is often referred to as an ore characteristic. The ore resistance to grinding and energy consumption can be expressed using the work index and Bond’s Third Theory. The Bond Third Theory method is widely used in the design of the grinding cycle, selection of grinding equipment, determination of required grinding power, and performance evaluation of the process. Despite widespread use for more than seventy years, doing a precise and complete Bond test can be challenging due to a variety of restrictions imposed by Bond. The initial size of the sample is strictly defined to be −3.35 mm. This paper describes the methodology for the determination of the Bond work index when coarse or fine raw material is found in the initial sample (i.e. when the initial sample not less than 3.35 mm).