scholarly journals Coal mining cost models. Final report. Volume I. Underground mines

1977 ◽  
Author(s):  
G. Toth
Keyword(s):  
Coal Mining ◽  
Underground Mines ◽  
Final Report ◽  
Cost Models

scholarly journals Cross-Sectional Survey of Musculoskeletal Disorders in Workers Practicing Traditional Methods of Underground Coal Mining

2020 ◽  
Vol 17 (7) ◽  
pp. 2566
Author(s):  
Madiha Ijaz ◽  
Sajid Rashid Ahmad ◽  
Muhammad M. Akram ◽  
Steven M. Thygerson ◽  
Falaq Ali Nadeem ◽  
...  
Keyword(s):  
Coal Mining ◽  
Upper Limb ◽  
Lower Limb ◽  
Lower Limbs ◽  
Underground Mines ◽  
Upper Limbs ◽  
Underground Coal Mining ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
R Programming

Background: In subcontinental underground mines, coal mining is carried out manually and requires many laborers to practice traditional means of coal excavation. Each task of this occupation disturbs workers’ musculoskeletal order. In order to propose and practice possible ergonomic interventions, it is necessary to know what tasks (drilling and blasting, coal cutting, dumping, transporting, timbering and supporting, loading and unloading) cause disorder in either upper limbs, lower limbs, or both. Methods: To this end, R-programming, version R 3.1.2 and SPSS, software 20, were used to calculate data obtained by studying 260 workers (working at different tasks of coal mining) from 20 mines of four districts of Punjab, Pakistan. In addition, a Standard Nordic Musculoskeletal Questionnaire (SNMQ) and Rapid Upper Limb Assessment (RULA) sheet were used to collect data and to analyze postures respectively. Results: In multi regression models, significance of the five tasks for upper and lower limb disorder is 0.00, which means that task based prevalence of upper and lower limb disorders are common in underground coal mines. The results of the multiple bar chart showed that 96 coal cutters got upper limb disorders and 82 got lower limb disorders. The task of timbering and supporting was shown to be dangerous for the lower limbs and relatively less dangerous for the upper limbs, with 25 workers reporting pain in their lower limbs, and 19 workers reporting pain in their upper limbs. Documented on the RULA sheet, all tasks got the maximum possible score (7), meaning that each of these tasks pose a threat to the posture of 100% of workers. The majority of participants (182) fell in the age group of 26 to 35 years. Of those workers, 131 reported pain in the lower limbs and slight discomfort (128) in the upper limbs. The significance value of age was 0.00 for upper limb disorder and was 0.012 for lower limb disorder. Frequency graphs show age in direct proportion to severity of pain while in inverse proportion with number of repetitions performed per min. Conclusions: All findings infer that each task of underground coal mining inflicts different levels of disorder in a workers’ musculoskeletal structure of the upper and lower limbs. It highlighted the need for urgent intervention in postural aspects of each task.

scholarly journals Large Deformation Mechanics of Gob-Side Roadway and Its Controlling Methods in Deep Coal Mining: A Case Study

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Jianwei Zheng ◽  
Wenjun Ju ◽  
Xiaodong Sun ◽  
Zhongwei Li ◽  
Shuai Wang ◽  
...  
Keyword(s):  
Stress Field ◽  
Large Deformation ◽  
Coal Mining ◽  
Tectonic Stress ◽  
In Situ Stress ◽  
Field Analysis ◽  
Underground Mines ◽  
Roof Structure ◽  
Deformation Mechanics

Maintaining surrounding rock mass stability of roadways is essential to the safety of deep coal mining. In this study, the No. 2-2092 roadway of the No. 2-209 mining face in Ganhe coal was taken as the target roadway for field analysis. The selected region can be considered a typical area with dominating geological tectonic stress, based on the geological survey and in situ stress results. A mechanical model of roadway overburdens was developed to analyse the large deformation and stress field distribution. It is found that the large deformation is caused by the combined superposed stress field including laterally transferred stress formed in structures at overlying strata, mining-induced advanced abutment pressure, and the regional in situ stress. Thus, a Two-Direction Hydrofracturing Technique (TDHT) was proposed to reduce the pressure of the No. 2-2092 roadway by altering the roof structure in the influenced zones. Compared with the original roadway without fracturing, it is found that the roof to floor convergence has dropped by nearly 47% after fracturing; the displacement of sidewalls has reduced by almost 31%, demonstrating the effectiveness of the proposed method in pressure relief. Results from this study can provide guidance on controlling the large deformation of roadways in deep underground mines.

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