Geologic considerations in underground coal mining system design

Geologic characteristics of coal resources which may impact new extraction technologies are identified and described to aid system designers and planners in their task of designing advanced coal extraction systems for the central Appalachian region. These geologic conditions are then organized into a matrix identified as the baseline mine concept. A sample region, eastern Kentucy is analyzed using both the developed baseline mine concept and the traditional geologic investigative approach

Accuracy of physician self‐estimation of time spent during patient care in the emergency department

Abstract Objective Accurate measurement of physicians’ time spent during patient care stands to inform emergency department (ED) improvement efforts. Direct observation is time consuming and cost prohibitive, so we sought to determine if physician self‐estimation of time spent during patient care was accurate. Methods We performed a prospective, convenience‐sample study in which research assistants measured time spent by ED physicians in patient care. At the conclusion of each observed encounter, physicians estimated their time spent. Using Mann–Whitney U tests and Spearman's rho, we compared physician estimates to actual time spent and assessed for associations of encounter characteristics and physician estimation. Results Among 214 encounters across 10 physicians, we observed a medium‐sized correlation between actual and estimated time (Spearman's rho = 0.63, p < 0.001), and in aggregate, physicians underestimated time spent by a median of 0.1 min. An equal number of encounters were overestimated and underestimated. Underestimated encounters were underestimated by a median of 5.1 min (interquartile range [IQR] 2.5–9.8) and overestimated encounters were overestimated by a median of 4.3 min (IQR 2.5–11.6)—26.3% and 27.9% discrepancy, respectively. In terms of actual time spent, underestimated encounters (median 19.3 min, IQR 13.5–28.3) were significantly longer than overestimated encounters (median 15.3 min, IQR 11.3–20.5) (p < 0.001). Conclusions Physician self‐estimation of time spent was accurate in aggregate, providing evidence that it is a valid surrogate marker for larger‐scale process improvement and research activities, but likely not at the encounter level. Investigations exploring mechanisms to augment physician self‐estimation, including modeling and technological support, may yield pathways to make self‐estimation valid also at the encounter level

Evaluate fundamental approaches to longwall dust control. Phase III report

The overall objective of the contract is to evaluate the effectiveness of available dust control technology for double-drum shearer longwall sections in a coordinated, systematic program at a few longwall test sections and to make the results available to the entire coal mining industry. This program is investigating nine different dust control techniques. These nine subprograms encompass a broad range of dust control measures ranging from administrative controls to new hardware. They span not only presently employed methods but also those recently adopted in the United States and those proposed for the future. This report documents the Phase III effort on each of the subprograms. For clarity, the report is divided in sections by subprogram as follows: Section 2, Subprogram A - passive barriers/spray air movers for dust control; Section 3, Subprogram B - practical aspects of deep cutting; Section 4, Subprogram C - stage loader dust control; Section 5, Subprogram D - longwall automation technology; Section 6, Subprogram E - longwall application of ventilation curtains; Section 7, Subprogram F - reversed drum rotation; Section 8, Subprogram G - reduction of shield generated dust; Section 9, Subprogram H - air canopies for longwalls; and Section 10, Subprogram I - mining practices. 43 figures, 11 tables