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Extension of ore pass length has become increasingly critical for optimising energy-efficient underground mining operations. Long and ultra-long ore passes, spanning from 300 to 700 m, can significantly improve the functionality and viability of underground mass mining operations though suboptimal performance has an extremely adverse impact on production. The public domain lacks substantial information regarding the primary engineering, geological, and geotechnical risks and challenges associated with the design, implementation, operation, and maintenance of such long ore passes. Therefore, the aggregation of past experiences and the insights of experts assume paramount significance. An innovative methodology is introduced to address this evident data deficiency and to establish comprehensive guidelines for the resilient design of such lengthy ore passes — combining gap analysis with expert elicitation techniques. This equips design engineers with the necessary tools to formulate and adapt strategies for assessing the numerous challenges and uncertainties that invariably accompany their projects. Expert elicitation techniques are summarised, and a gap analysis is conducted with subject matter experts, from various countries, collating their extensive ore pass design experience, to create a comprehensive list of effective parameters and key risks that must be considered. Quantitative analysis of the survey results enabled the identification and ranking of the numerous factors affecting the design, operation, and maintenance of long and ultra-long ore passes and highlights the complex technical challenges (substantial damage from rock particle impact, increased dynamic mining stresses leading to failure, air-blasts and back blasts, dust, preferential flow, turbulent and dynamic material flow) that are uncommon in shorter ore passes. Additionally, increasing length heightens the probability of intersecting weak rock or discontinuities, leading to a higher risk of structural failure and instabilities. Faulting, folding, and large-scale structures are also critical geological factors to be considered in the design of such structures. The key geotechnical factor is also the rock type surrounding the pass. Experts highlighted the lack of clear guidelines for decision-making, resilient design, and construction so this work suggests future investigations to determine the complex interaction between the effective parameters, using approaches like the rock engineering system, discovery of cascading hazards, and optimal controls.

Salinity is one of the major abiotic factors limiting crop production worldwide. To assess salinity stress tolerance of wild (Hordeum vulgaressp. spontaneumL.) and cultivated (H. vulgaressp. vulgareL.) barley genotypes, a two-year field experiment was carried out. Plant height, days to heading, days to anthesis, days to maturity, spike length, grain yield, and yield components were evaluated under normal and salinity stress conditions. The stress stability index (SSI), tolerance index (TOL), yield index (YI), stress tolerance index (STI), geometric mean productivity (GMP), mean productivity (MP), and yield stability index (YSI) were the tolerance indices used in this study. The results showed significant effects of salinity stress and genotype on the measured and calculated variables. The wild genotypes were less affected by salinity stress than the cultivated ones and thus were far superior for the stability indices for yield (STI and YSI). On the other hand, barley cultivars were superior for yield obtained under normal (Yp) and saline (Ys) conditions, MP, GMP, and TOL. A strong relationship was found between grain yield and three indices (STI, YI, and YSI). Ultimately, cluster and principal component analyses suggested that the implementation of STI and YSI in the screening of the wild genotypes for salinity tolerance results in a more robust determination of the most salinity tolerant genotypes.

Abstract: Objective. To compare 201thallium (T1) uptake and SPECT with MRI in children with brainstem gliomas. Materials and methods. Ten children with brainstem gliomas were prospectively evaluated by 201Tl-SPECT and MRI. Histological verification was obtained in eight children – two died prior to surgery. Quantitative thallium uptake index (UI) was obtainable in five cases and was compared to tumour grade. In addition, two patients with known benign brainstem lesions (neurofibromatosis and tuberculoma) were similarly prospectively evaluated. Results. All children with brainstem glioma accumulated thallium. (Mean U1 3.23, 100 % sensitivity). The single patient with brainstem tuberculoma also accumulated thallium (UI 2.80, 91.7 % specificity). There was no correlation between thallium uptake and tumour grade. Uptake could not be conclusively correlated with the following MR features: gadolinium enhancement, exophytic or intrinsic gliomas, necrosis and location of glioma within the brainstem. Conclusions. 201Tl-SPECT is a promising imaging adjunct in the assessment of childhood brainstem gliomas.