Search

Given the recent focus on powered haulage incidents within the US mining sector, an appraisal of collision avoidance/warning systems (CXSs) through the lens of the available research literature is timely. This paper describes a rapid review that identifies, characterizes, and classifies the research literature to evaluate the maturity of CXS technology through the application of a Technology Readiness Assessment. Systematic search methods were applied to three electronic databases, and relevant articles were identified through the application of inclusion and exclusion criteria. Sixty-four articles from 2000 to 2020 met these criteria and were categorized into seven CXS technology categories. Review and assessment of the articles indicates that much of the literature-based evidence for CXS technology lies within lower levels of maturity (i.e., components and prototypes tested under laboratory conditions and in relevant environments). However, less evidence exists for CXS technology at higher levels of maturity (i.e., complete systems evaluated within operational environments) despite the existence of commercial products in the marketplace. This lack of evidence at higher maturity levels within the scientific literature highlights the need for systematic peer-reviewed research to evaluate the performance of CXS technologies and demonstrate the efficacy of prototypes or commercial products, which could be fostered by more collaboration between academia, research institutions, manufacturers, and mining companies. Additionally, results of the review reveal that most of the literature relevant to CXS technologies is focused on vehicle-to-vehicle interactions. However, this contrasts with haul truck fatal accident statistics that indicate that most haul truck fatal accidents are due to vehicle-to-environment interactions (e.g., traveling through a berm). Lastly, the relatively small amount of literature and segmented nature of the included studies suggests that there is a need for incremental progress or more stepwise research that would facilitate the improvement of CXS technologies over time. This progression over time could be achieved through continued long-term interest and support for CXS technology research.

Mineworkers face a challenging and dynamic work environment every workday. To maintain a safe workplace, mineworkers must be able to recognize worksite hazards while they perform their jobs. Though hazard recognition is a critical skill, recent research from the National Institute for Occupational Safety and Health (NIOSH) indicates that mineworkers fail to identify a significant number of hazards. To further the understanding of mineworkers’ hazard recognition ability and to begin to address hazard recognition performance, NIOSH researchers analyzed data collected during a laboratory research study to determine the effect of individual mineworker factors including risk attitude, work experience, and safety training on hazard recognition accuracy. The results of this study show that mineworker risk attitude and safety-specific work experience affect hazard recognition performance while hazard-specific safety training does not. These results suggest that some of these individual factors can be overcome through experience and training. Potential strategies that can be used to address these factors are also discussed.

Magnetic proximity detection systems (PDSs) are used with continuous mining machines (CMMs) to protect miners from striking and pinning accidents. Generators are used in a PDS to create magnetic fields covering the space around a CMM. The PDS determines the proximity of a miner relative to the CMM based on the magnetic flux density detected by a miner-wearable component (MWC) and simultaneously alerts the miner and stops the motion of the CMM if the miner is within a proximity that creates a striking hazard. A stable magnetic field is essential to the accuracy of the proximity calculations performed by the PDS. This paper presents the results of a systematic study of the magnetic influence of two types of steel structures found near a CMM—the body of the CMM itself and the wire mesh used for roof and rib control. The results show that the steel of the CMM body can change the magnetic field distribution and also alter electrical parameters of a PDS by changing its generator current. The study also shows that, depending on the distance between the wire mesh and a generator, the magnetic field can also be altered.

Accident data indicates that mobile haulage poses a significant pinning, crushing, and striking risk. Proximity detection systems (PDSs) have the potential to protect mineworkers from these risks. However, unintended consequences of mobile PDSs can undermine the safety benefit they provide. Soliciting iterative user input can improve the design process. Users help provide a critical understanding of how mobile PDSs may hinder normal operation and endanger mineworkers. Researchers explored users’ perspectives by conducting interviews with mineworkers from seven mines that have installed mobile PDSs on some of their haulage equipment. Mineworkers reported that mobile PDSs affect loading, tramming, section setup, maintenance, and general work on the section. Mineworkers discussed the operational effects and increased burden, exposure, and risk. Mineworkers also suggested that improved task compatibility, training, logistics, and PDS performance might help address some of these identified issues. This paper also gives additional insights into mobile PDS design and implementation.

Recent advances in computing, rendering, and display technologies have generated increased accessibility for virtual reality (VR). VR allows the creation of dynamic, high-fidelity environments to simulate dangerous situations, test conditions, and visualize concepts. Consequently, numerous products have been developed, but many of these are limited in scope. Therefore, the National Institute for Occupational Safety and Health researchers developed a VR framework, called VR Mine, to rapidly create an underground mine for human data collection, simulation, visualization, and training. This paper describes the features of VR Mine using self-escape and proximity detection as case studies. Features include mine generation, simulated networks, proximity detection systems, and the integration and visualization of real-time ventilation models.

Proximity detection systems (PDSs) for mobile machines have the potential to decrease injuries and fatalities. Early adopters of the technology have identified some challenges, which present an opportunity to explore and improve the integration of mobile PDSs in underground coal mines. The current research study applied the task-technology fit framework to investigate the fit between mobile PDS technology and mining relative to health and safety, from the perspective of leaders at two coal mines. Quantitative results from the study show that mine leaders evaluated mobile PDS favorably for training and ease of use, system feedback, user authorization and experience, and less favorably for safety, compatibility, task completion, and reliability. Qualitative results reveal specific task, mine, and system characteristics that may have influenced leaders’ evaluations. The study includes considerations and suggestions for safe technology integration.

Active mining operations are complex, dynamic environments that can present workers with an array of potential safety and health challenges. From missing fire extinguishers to large equipment and falling rocks, hazards exist that mineworkers must be cognizant of to keep themselves and their coworkers safe. While hazard identification is a key skill that mineworkers must possess to ensure workplace safety, the location and perceived risk of the hazards may alter this ability. To further explore these effects, NIOSH researchers conducted a study to characterize how mineworkers search for and identify hazards. Researchers asked participants to search 32 static panoramic scenes depicting typical locations at a surface stone mine—pit, plant, roadway, and shop—with each containing zero to seven hazards. Mineworkers tended to miss hazards when they were in clusters—i.e., where two or more hazards appeared within the worker’s central field of view. This paper examines the relationship of clustered hazards, perceived risk and identification accuracy and how location and experience affect it. Based on the results, strategies will be suggested that mineworkers can use to help identify hazards in their workplace.

To perform a successful workplace examination, mineworkers must be able to find and fix hazards at their workplace. NIOSH recently completed a laboratory study to identify differences in hazard recognition performance for mineworkers, safety professionals, and mining engineering students tasked with performing a simulated workplace examination in a virtual environment. The laboratory methodology and study results were used to develop a training product aimed at improving mineworker safety. The purpose of the current chapter is to describe the efforts that were taken to modify the laboratory workplace examination simulation into a portable software tool called EXAMiner, which can be used for data collection and training purposes in the field. This chapter provides an explanation of the literature and results from the NIOSH laboratory research studies used to inform and motivate development of EXAMiner. In addition, the software specifications are explained.

As miners are expected to wear more and more equipment, space and capacity on their mining belt is becoming scarce. To combat this, several companies have recently developed vests for mining. We explored the usability, acceptance, and performance of one of the mining vests through a field evaluation. A total of 18 miners across various positions were recruited from high and med/low seam underground coal mines to wear a mining vest over a six-week period. Results confirm that comfort, especially related to overhead work, was a key factor to the usability of the vests, and comfort was a bigger factor in the lower seam mine than the higher. Reports of various other factors are included in this publication. Despite other concerns, the miners remained positive and interested in the concept of a mining vest, especially for certain occupations. With some modification, the mining vest could be an effective way to house the necessary equipment traditionally worn on a belt.

Mine workers are expected to remain vigilant and successfully identify and mitigate hazards in both routine and non-routine locations. The goal of the current research project is to better understand how workers search and identify hazards. NIOSH researchers developed a data collection setup to measure a subject’s gaze, head position, and reaction time while examining 360° 2D-panoramic images at a surface mine. The data is integrated in semi real-time to determine region of interest (ROI) hit accuracy for hazards within the images. The purpose of this paper is to discuss the development and implementation of the hardware and software. The following aspects of the setup will be explored in the paper: (1) environment selection, (2) image creation, (3) stimulus display, (4) synchronization, (5) gaze mapping, and (6) region of interest (ROI) hit calculation.

The different types of glazing systems currently in use today are described. This paper is directed toward wet glazing only and specifically the use of preformed butyl elastomeric tape. The development of a suitable tape formulation necessitates understanding the demands placed on the tape while in service. Adhesion to substrates, squeeze-out under load, pump out resistance, compression-deflection properties at various temperatures, and durability under long-term aging are typical parameters of a quality tape. Tests that define these characteristics and typical data are presented. Selection of tape is dependent upon whether the system requires a compressible, noncompressible, or shimmed tape. Installation techniques including the use of liquid sealants as well as proper joint preparation are discussed. Status of ASTM Subcommittee C24.50 on Preformed Tape Sealants efforts in test methods and specifications are discussed.

Inhibition of Thymidylate Synthase (TS) by the 5-Fluorouracil (5Fu) active metabolite Fluoro-deoxy-uridine-monophosphate (FdUMP) is considered to be the main mechanism of action of 5Fu. TS level from tumors and normal mucosa of 62 untreated patients who underwent surgery for primary colorectal adenocarcinoma was performed. The aim of this study was to evaluate the possibility of considering the TS level as a prognostic factor of the disease. A large variation in the level of the enzyme was found among tumors. Our data demonstrate that there is no association with age, sex, and tumor size; however there are significant relationships between TS levels and staging and histological grading. In fact the TS values are higher in Dukes' A and in G1 than in Dukes' D and G3 tumors (p0.05). Another significant association has been found between the TS level and tumor site: pts with right colon neoplasias had higher TS levels than pts with left and rectum ones. An interesting trend was found between the TS levels and survival parameters. Pts who had lower TS levels had a significantly increased risk of death (p0.05) over pts with a higher outcome. Our data support the hypothesis that a high TS level is a favourable prognostic factor in human untreated colorectal carcinomas according to our previous preliminary data (1).

Morphine concentrations in plasma and CSF after i.m. and epidural morphine administration were assayed in patients undergoing surgery of the low abdomen. Morphine concentration in CSF after i.m. administration of this drug is remarkably lower than morphine concentration in plasma. The highest value is attained in CSF after about 90' and is followed by a slow downsloping to lowest values, which were observed 4 hours after drug administration. Kinetics of morphine passage into plasma after epidural administration is similar to that found after i.m. administration. In the latter experimental condition (epidural administration), concentrations of morphine in CSF 30' after administration are markedly lower than those found in plasma. However, 60 min. after epidural administration plasma and CSF morphine concentrations are similar, in particular CSF concentrations are 4 to 8 times higher than those obtained after i.m. administration. Such high levels persists for a long time.

Summary Groups of male rats were treated with antihypertensive drugs (alpha-methyl-dopa, clonidine, propranolol, reserpine, diazoxide) which were administered under conditions causing the onset of high plasma renin activity (PRA) and high plasma and urine aldosterone levels, i.e. together with distilled water load (5% of body weight). Alpha-methyl-dopa and propranolol, which fail to significantly alter PRA and plasma aldosterone levels when administered without distilled water load, cause a marked decrease of plasma and urine aldosterone levels and of PRA when administered together with distilled water load, while diazoxide, and reserpine cause a marked increase of these values. Clonidine causes significant decreases of PRA and plasma aldosterone levels in both experimental situations. Increases of PRA and of plasma aldosterone levels occur also in rats treated with diazoxide associated with propranolol and in those treated with an association of reserpine and propranolol. The highest values of plasma aldosterone levels were found in rats treated with reserpine for two days and receiving a further dose of reserpine associated with propranolol on the third day, which fact was ascribed to the reduction of peripheral vascular resistance and of plasma flow in the kidney (as shown by decreased diuresis) brought about by propranolol and followed by a marked compensatory activation of the renin-angiotensin-aldosterone system. Moreover there is no apparent correlation between the antihypertensive effect and the variations of the renin-angiotensin-aldosterone system.

The data reported in the present paper refer to quantitative variations of plasma renin activity (PRA.) and of plasma aldosterone levels in rats after adiministration of saline, chrystalloid and colloid solutions. In our experimental conditions PRA and plasma aldosterone levels were shown to increase significantly after administration of distilled water and glucose solution. Variations of PRA and plasma aldosterone levels were only slight when plasma volume was made to increase due to administration of polyvinylpirrolidone solution. PRA, instead, was significantly lower in rats having received saline salution.

Resume Dans le contexte de la reaction endocrinienne et metabolique a l'anesthesie et a la chirurgie, les effets de l'isoflurane sur l'axe hypothalamohypophysocorticosurrenalien et le systeme hypothalamothyroidien ont ete etudies. L'ACTH, le cortisol, la TSH, la T3, la T4 et la prolactine ont ete doses chez 16 patients avant et au cours de l'intervention chirurgicale sous anesthesie avec isoflurane. Les resultats objectivent une augmentation significative des valeurs de la prolactine, du cortisol et de T4, permettant de conclure que l'isoflurane ne bloque pas l'augmentation du taux plasmatique de ces hormones au cours du stress chirurgical et se comporte donc a ce point de vue comme l'enflurane.

O-ring seals of selected elastomeric and compliant materials were evaluated for resistance to liquid rocket fuels and oxidizers in a simulated end-use test. Oxidizers were nitrogen tetroxide, chlorine trifluoride, and 90 per cent hydrogen peroxide; fuels were mixed hydrazines, pentaborane, and Hybaline A-5. Tests were made at 73° F with all fluids; further, the effect of elevated temperature (160° F) on seals was evaluated in nitrogen tetroxide, hydrogen peroxide, and mixed hydrazines. At 73° F only polytetrafluoroethylene was resistant to all of the fluids; however, elastomeric materials were found which were satisfactory for specific fuel or oxidizer systems. Butyl and ethylene propylene rubber appear satisfactory for long term storage in the presence of mixed hydrazines and Hybaline A-5. The fluorocarbons appeared best of the elastomeric materials for use with pentaborane and hydrogen peroxide.

PRA, plasma and urine aldosterone levels and plasma digoxin were measured in rats in which digoxin had been administered under conditions of high PRA and high aldosterone levels experimentally induced by administering distilled water load and in rats in which digoxin had been administered without distilled water load. Results show that under conditions of high PRA and high aldosterone levels, plasma digoxin concentrations as measured 6 h after treatment were higher (45,3%) than in rats having received digoxin without water load. In assays carried out on rats sacrificed 12 h after digoxin treatment (with or without water load) all values approach basic levels again, thus suggesting that in rats too aldosterone might compete with digoxin at the level of tubular excretion.

Summary The data reported in the present paper refer to quantitative variations of plasma renin activity and plasma aldosterone levels after administration of alpha-blocking agents, i.e. phentolamine, phenoxybenzamine and gihydroergotoxin derivatives, either to rats kept on a standard diet with water ad libitum or to rats receiving distilled water load, the latter treatment causing an increase of both plasma renin activity and plasma aldosterone levels if compared to control values. No strict correlation between (a) drug-induced modifications of plasma renin activity and plasma aldosterone levels and (b) blood pressure drop caused by the same drugs was shown to occur under either experimental condition. Infact phentolamine and dihydroergotoxin derivatives exert all a more or less marked hypotensive action, which may be associated with relatively high plasma renin activita and plasma aldosterone levels, as is the case with phentolamine and phenoxybenzamine, or with low PRA and low plasma aldosterone levels, as is the case with dihydroergotoxin derivatives.

Summary Groups of 10 rats were treated with diuretics (furosemide, hydrochlorotiazide, spironolactone, triamterene) under conditions of high or low plasma renin activity (PRA) brought about by administering distilled water or saline load, respectively. PRA, plasma aldosterone levels, urine aldosterone concentration as well as diuresis and Na+ and K+ excretion were

The effects during surgery of a new halogenated volatile anaesthetic, isoflurane, on the hypothalamo-hypophyseal-thyroid-suprarenal axis were studied. In fact, it was important to prove whether this new halogenated anaesthetic would provide better protection, for the patient, from surgery and anaesthetic stress compared with other anaesthetic agents in use. The study was carried out in 16 young class ASA I patients who were to undergo appendicectomy. Before and during operation, blood was taken to measure ACTH, cortisol, TSH, T3, T4 and PRL plasma levels. A remarkable increase of PRL, cortisol and T4 plasmatic rate was found, especially at the end of the operation. It was concluded that isoflurane, just like enflurane, did not prevent the increase of PRL, cortisol and T4 that usually takes place during surgery.

In the last years many Authors on the grounds of clinical and experimental studies have assumed the possibility of a connection between the prolactin and the breast pathology especially the carcionoma. In the present work the Authors give the results of the doses of the prolactin plasmatic basal levels, performed on 122 subjects belonging to 4 different groups: 1) patients with carcinoma of the breast; 2) patients with benign tumors of the breast; 3) patients with fibrocystic breast disease; 4) subjects of control. In patients who have undergone an operation further doses of blood prolactin have been carried out on 5th, 10th, 30th day after operation. On the grounds of such results the Authors propose new hypothesis of work wich will help to clear this problem.

Literature was surveyed with regard to the effects of long-term storage on the properties of elastomeric compounds. Data showed that most elastomeric compounds aged well. Elongation at break appeared to be the property most commonly affected by age deterioration, although compression set and change in strain also are affected. (Author)