INVESTIGATION OF THE EFFECTIVENESS OF AN INTEGRATED FLOODED-BED DUST SCRUBBER ON A LONGWALL SHEARER THROUGH LABORATORY TESTING AND CFD SIMULATION

Dust generation at an underground coal mine working face continues to be a health and safety issue. Prolonged exposure to high concentrations of airborne respirable dust can cause a debilitating and often fatal respiratory disease called Black Lung. In addition, the deposition of float dust in mine return airways poses a serious safety hazard if not sufficiently diluted with inert rock dust. A localized methane explosion can transition into a self-propagating dust explosion. Since dust is a byproduct of various mining activities, such as cutting and loading, crushing, and transportation, the dust-related issues cannot be totally eliminated. However, the adverse health effects and safety concerns can be minimized if a significant amount of the generated dust is removed from the ventilation air by a mechanical device, such as a dust scrubber. Over the last three decades, flooded-bed dust scrubbers integrated into continuous miners have been successfully applied for capturing and removing airborne dust generated at the working face. According to the National Institute for Occupational Safety and Health (NIOSH), a flooded-bed scrubber can achieve more than 90% capture and cleaning efficiencies under optimum conditions. Although flooded-bed scrubbers have proven useful in the vast majority of cases, they have not yet been successfully applied to a longwall face. In the United States, numerous attempts have been made to reduce dust concentration at a longwall face through the application of a scrubber; but, none were successfully implemented. Encouraged by the successful use of a flooded-bed scrubber system at continuous miner faces, this research revisits the flooded-bed scrubber concept for a longwall shearer. For this investigation, a full-scale physical model of a Joy 7LS longwall shearer, modified with an integrated flooded-bed dust scrubber, was designed and fabricated at the University of Kentucky. The scope of work for this research was limited to capturing and cleaning dust generated near the shearer headgate drum only. The mock-up was transported to, and assembled in, the full-scale longwall dust gallery at the NIOSH Pittsburgh Research Laboratory (PRL). Tests were conducted to examine: (1) the effect of the scrubber on headgate-drum dust reduction and (2) the combined effect of the scrubber and splitter sprays on headgate drum dust reduction. Analysis of test results for the scrubber-alone condition indicates a significant dust reduction of up to 57% in the return airway and 85% in the test gallery walkway, whereas the combination of scrubber and splitter-arm sprays shows dust reduction of up to 61% and 96% in the return and walkway, respectively. These results indicate that a flooded-bed scrubber integrated into a longwall shearer can be used as a viable technique to reduce a large portion of airborne dust at a longwall face. Subsequently, a Computational Fluid Dynamics (CFD) model of the longwall gallery and shearer was developed and validated using the results of the experimental study. The CFD simulation results are in good agreement with the experimental results with a maximum of 9.7% variation. This validated CFD model can be used in future research to predict the effects of modifications to the scrubber system, including modifications to the scrubber inlet, to optimize the scrubber design, and to evaluate the effectiveness of adding a tailgate drum dust scrubber

Experimental and Numerical Investigation of the Effect of Integration of a Flooded-Bed Scrubber into a Longwall Shearer on Airflow along a Coal Mine Longwall Face

Dust control is one of the most difficult challenges for underground coal mine operators, especially longwall mine operators. The most widely used dust control technologies at a longwall section are ventilation air and water sprays, whereas a continuous miner section has the added advantage of having a dust scrubber built into the continuous miner. To test the potential benefits of integrating a flooded-bed scrubber into a longwall shearer, the authors designed and built a dust scrubber system for a full-scale mock-up of a longwall shearer. The mock-up was installed in the longwall test gallery at the Pittsburgh Research Laboratory (PRL) for testing. Air quantity surveys were performed at different cross-sections of the test gallery at a fixed face-air quantity, but at different scrubber airflow rates to quantify the distribution of air in the test gallery. Subsequently, a computational fluid dynamics (CFD) model of the PRL test gallery was developed and validated. In this study, the effect of the flooded-bed scrubber on airflow pattern in the test gallery is investigated using the validated CFD model. This model can be used further to predict the dust capture efficiency of the scrubber and to develop new techniques to reduce dust concentration in longwall sections

Scale modeling of dust capture through a flooded-bed dust scrubber integrated within a longwall shearer

Meeting federal dust standards at a longwall mine face is among the more difficult challenges for a longwall mine operator. With recent changes in federal dust regulations requiring lower worker exposure, maintaining compliance has become increasingly difficult. The authors recommend the concept of controlling respirable and float dust, which is inherent in longwall mining, through the application of a flooded-bed dust scrubber to a longwall shearer. A full-scale physical model of a longwall shearer, modified with an integrated flooded-bed scrubber, was designed and fabricated at the University of Kentucky to measure the effects of a flooded-bed scrubber on dust capture at a longwall face. The mockup was transported, assembled, and tested in the longwall dust gallery at the Pittsburgh Research Laboratory of the National Institute for Occupational Safety and Health (NIOSH). Test results indicated a dust reduction of up to 57% in the return airway of the longwall gallery. The test results were validated with Computational Fluid Dynamics (CFD) modeling with a maximum of 9.7% difference in results. The aim of the study was to test the flooded-bed scrubber concept with a longwall shearer on a half-scale model using the CFD modeling technique. The paper discusses the validation of the developed scaling laws through the results of CFD modeling on the full-scale porotype and half-scale model

Scale and numerical modeling to determine operating points of a non-clogging Vortecone filter in mining operation

Numerical and scale modeling studies of Vortecone, a pressure-driven wet-scrubber device for the efficient capture of over-sprayed paint in the automobile industry, are presented. In this manuscript, Vortecone was tested for removing dust particles from underground mining operations. The pressures required to operate Vortecone and the airflow rates through the Vortecone are the two most important factors for mine ventilation systems. This study used dry, no-particle conditions to obtain relationship between these two parameters and then designed a Vortecone filter ventilation system for mining operations. Commercial software, SC/Flow, was used to generate the CFD model with unstructured meshes and a series of numerical calculations were accomplished. Included in these were calculation of a 1/3rd scale model of Vortecone along with experimentation that was accomplished to validate the numerical predictions. The experiments were conducted to measure pressure drops for known airflow velocities at critical points within Vortecone. The scale model experimental results agreed very well with the CFD numerical calculations. For scaling the performance of the 1/3rd scale model to full scale, the scaling laws were developed using the law approach; they are discussed along with the feasibility of the Vortecone filter system for underground mining operations

Experimental and Numerical Investigation of the Effect of Integration of a Flooded-Bed Scrubber into a Longwall Shearer on Airflow along a Coal Mine Longwall Face

Dust control is one of the most difficult challenges for underground coal mine operators, especially longwall mine operators. The most widely used dust control technologies at a longwall section are ventilation air and water sprays, whereas a continuous miner section has the added advantage of having a dust scrubber built into the continuous miner. To test the potential benefits of integrating a flooded-bed scrubber into a longwall shearer, the authors designed and built a dust scrubber system for a full-scale mock-up of a longwall shearer. The mock-up was installed in the longwall test gallery at the Pittsburgh Research Laboratory (PRL) for testing. Air quantity surveys were performed at different cross-sections of the test gallery at a fixed face-air quantity, but at different scrubber airflow rates to quantify the distribution of air in the test gallery. Subsequently, a computational fluid dynamics (CFD) model of the PRL test gallery was developed and validated. In this study, the effect of the flooded-bed scrubber on airflow pattern in the test gallery is investigated using the validated CFD model. This model can be used further to predict the dust capture efficiency of the scrubber and to develop new techniques to reduce dust concentration in longwall sections

Pengembangan Media Komik Dalam Pembelajaran Membaca Teks Cerita Rakyat Kelas VII-A SMP Tamansiswa

Penelitian dengan judul “Pengembangan Media Komik Dalam Pembelajaran Membaca Teks Cerita Rakyat Kelas VII-A SMP Tamansiswa Kota Mojokerto” merupakan penelitian yang akan mengahasilkan produk berupa media pembelajaran komik. Media tersebut dapat dijadikan alternatif dalam kegiatan pembelajaran, seperti pada pembelajaran teks cerita rakyat. Media pembelajaran ini akan membuat suasana baru dalam pembelajaran karena siswa tidak hanya menggunakan buku atau papan tulis seperti yang biasa mereka lakukan melainkan belajar dengan menggunakan media pembelajaran komik. Hal tersebut akan membuat suasana belajar menjadi lebih menyenangkan. Dengan menggunakan medhia pembelajaran komik ini, merupakan hal baru bagi siswa kelas VII-A, sehingga dalam kegiatan ini mampu menumbuhkan rasa semangat siswa dalam belajar. Ketika siswa mempunyai rasa semangat dalam belajar, maka akan mempermudah siswa dalam menerima pembelajaran sehinggamemberi pengaruh nilai yang baik. Dengan demikian media ini juga digunakan sebagai contoh dalam pembelajaran lain. Karena dengan penggunaan media, selain memicu semangat siswa media tersebut juga mempermudah guru dalam memberikan materi kepada peserta didik. Kata kunci : pengembangan media pembelajaran, kualitas media pembelajaran, pembelajaran teks cerita rakyat