Causes and Methods of Reducing Dilution at Seabee Gold Mine

The failure of waste rock from the hangingwall and footwall of open panels dilutes ore grades, creates significant costs for underground mines and can reduce production rates. This research investigates the mechanisms causing dilution from the hangingwall and footwall of panels at SSR Mining’s Seabee Gold Mine, located in northern Saskatchewan. To conduct this research, estimations were made regarding the rock mass conditions and stress in panels so conventional analysis techniques for dilution could be applied. Underground field mapping and lab testing were conducted, and a new methodology was developed to assess large scale joint irregularities. Three joint sets were identified with Q’ ranging from 10.6 to 14.1 for the panel hangingwall. An instrumentation program was conducted with both closure stations and an extensometer. New data interpretation techniques were applied which suggested stresses normal to the ore body reached a stress of approximately 92 MPa, prior to panel mining. Conventional empirical dilution estimation analyses indicated that less than 0.5 metres of dilution should be expected from both the hanging wall and the footwall of all panels assessed at the Seabee Mine. Cavity Monitoring Survey (CMS) data was collected and interpreted and many dilution values were measured to be well in excess of 0.5 metres. It is known that open panel dilution can be caused by many mechanisms. These mechanisms, or causes of dilution, include: • rock mass instability due to panel dimensions exceeding stable limits which would be represented by an arch shaped failure; • panel top sill and bottom sill drifts extending past the ore – waste contact; and, • blast hole deviation causing the hangingwall and footwall rocks to be blasted. Each of these mechanisms have characteristic failure or dilution profiles. The approach to this research has been to link the detailed geometry of the hangingwall and footwall surfaces from which dilution has occurred, to the expected failure geometry from the common causes of panel dilution. This research shows that of the three failure mechanisms listed above, the dominant failure mechanism is based on geometrical instability represented by an arch shaped failure. The failure mechanisms of panel undercutting due to sill drifts extending past the ore – waste contact and blast hole deviation were not found to be significant. Efforts to minimize panel dilution are recommended based on their cause, and these efforts cannot be effective without an understanding of the mechanisms influencing dilution. The methodology developed in this thesis is applicable to all underground hard rock mining operations

International Students as ‘Privileged’: Challenging the Narrative

International students are typically described as a privileged and affluent group. This study challenges this narrative, and examines the experiences of socioeconomically disadvantaged international students, through an exploratory mixed-methods study. To date, there has been limited empirical work recognising heterogeneity in the socioeconomic backgrounds of international students. This paper reports on the quantitative scoping exercise of a self-report questionnaire undertaken by 102 international students studying at UK universities, with 37 per cent identifying as ‘working-class’. The findings indicated that international students identifying as ‘working-class’ were more likely to be undertaking paid employment with longer hours in comparison to their middle-class counterparts. Moreover, ‘satisfaction with life’ and ‘support networks’ were considerably lower for those reporting socio-economic disadvantage. This study has highlighted a lacuna in the international student research literature. Furthermore, the findings indicate universities need to revisit the nexus of research on disadvantaged ‘home’ students and cultural adjustment models to ensure suitable support structures are offered to this under-researched group of international students

Connecting with family, friends and others: informal caregiving among international postgraduate researchers in a British University

\ua9 2024, STAR Scholars Network. All rights reserved.This article casts light on informal caregiving, an essential aspect of the international postgraduate researcher (PGR) experience, but which is often invisible in literature and discourses on international education. Drawing from qualitative semi-structured interviews with international PGRs in a British university, it highlights their dual role as care recipients and lesser known caregivers across transnational and local spaces. It gives insights into the forms and dynamics of care that they give to and receive from family, friends and others, uncovering the emotional and affective aspects of undertaking a postgraduate research degree overseas which impact on their mental wellbeing. The findings have implications for the improvement of university support for international PGRs which has relevance for the wider international student community

VIBCO Bin Variation System

VIBCO vibrators has tasked the team in designing an internal bin fixture that aids in material flow for the food, pharmaceutical, and chemical industries. This bin fixture must be adaptable to various sized diameter bins in order to create a cost efficient product that does not require the customer to make any physical changes to their bin. Lastly the internal fixture must be capable of raising and lowering in a way that gives the customer the ability to control material flow. The team began research on competitor systems that are currently on the market in this industry. After completing this research, it was determined that all of the competitor systems require the customer to make physical changes to their bin in order to implement the system. This being said it was imperative that the team design an internal fixture that can be easily installed without requiring the customer to edit their bin. From here design specifications were determined and discussed with the VIBCO engineering team to ensure that all of the bases were covered. In order to complete this task, the team began with brainstorming in order to determine some basic design specifications that would guide our 90 concepts generated. After analyzing each of the 90 concepts and a critical design review, two concepts were created by integrating and incorporating many elements of the entire spectrum of concept solutions. From here the team furthered research on different materials that would be strong, light weight, cost efficient, and high-corrosive resistant. After determining the different materials design work was furthered and a Solidworks design of the full internal bin system was created. Before finalizing any Solidworks designs the team crosschecked once again the proposed design with the competitors to ensure that this had not been done before. After completing and simulating a model of the proposed design the team performed a financial analysis and determined we are well under competitor pricing once this design is in full production. All of our other design specifications were met but the team would continue to make improvements. Once the design had been approved by VIBCO, parts were ordered and the build portion of the project began. Testing of the system soon followed at VIBCO using a bin they had on site. With the testing and data collected, redesign and improvements were able to be made to the original prototype

Abnormal Excitation-Contraction Coupling and Calcium Homeostasis in Myopathies and Cardiomyopathies

International audienceMuscle contraction requires specialized membrane structures with precise geometry and relies on the concerted interplay of electrical stimulation and Ca 2+ release, known as excitation-contraction coupling (ECC). The membrane structure hosting ECC is called triad in skeletal muscle and dyad in cardiac muscle, and structural or functional defects of triads and dyads have been observed in a variety of myopathies and cardiomyopathies. Based on their function, the proteins localized at the triad/dyad can be classified into three molecular pathways: the Ca 2+ release complex (CRC), store-operated Ca 2+ entry (SOCE), and membrane remodeling. All three are mechanistically linked, and consequently, aberrations in any of these pathways cause similar disease entities. This review provides an overview of the clinical and genetic spectrum of triad and dyad defects with a main focus of attention on the underlying pathomechanisms