UG2 pillar strength: Verification of the PlatMine formula

The research described in this paper was done to confirm the Upper Group 2 (UG2) PlatMine peak pillar strength formula (Watson et al., 2007), which was determined from a back-analysis of failed and unfailed pillars. Underground measurements were made on a stable pillar that was loaded by firstly reducing it's length and then by mining the surrounding pillars until pillar failure took place. The pillar was instrumented with suitably positioned strain cells and closure meters, which allowed both the average pillar stress and strain to be determined. The paper describes the methodology applied to identify a suitable position for the instrumentation, as well as the results. A stress/strain curve is presented for a UG2 pillar with a w/h ratio of 2.0, at Booysendal Platinum Mine. The measured pillar strength was similar to the predicted strength using the PlatMine pillar strength formula for UG2 pillars. The PlatMine formula has been successfully implemented on Booysendal Platinum Mine, and about 3 670 pillars have been cut without a single failure. An additional revenue of US$1.3 billion was calculated for the 25-year life of the mine as a direct result of the improved pillar design, given the January 2020 platinum group metals basket price. An extended life of mine and better mining efficiencies will also be realized.

Modeling and Comparative Analysis of Different Generic Cross Section B-Pillar Design in Roof Crush Impact

When a vehicle tips over onto its roof or side due to internal or external force on a vehicle is called Rollover impact. Rollover is a very critical impact compared to another mode of vehicle impacts. B-pillar and its cross-section design are very critical in the rollover impacts by reducing the cabin intrusion of vehicle. B-pillar absorbs most of the energy at the time of rollover and reduces the fatality rate of the passenger. In this work, a B-pillar finite element (FE) model is modeled to analyze as per FMVSS216a standard protocol to check the critical performance. Two generic cross-sections of the B-pillar are considered for preliminary assessment. This B-pillar designs FE model (cut model) are modeled and analyzed for FMVSS216a using LS-DYNA explicit code. The FMVS216a lab test is a quasi-static test and LS-DYNA is the well-accepted FEA tool to simulate the quasi-static test. LS-DYNA software is widely accepted as a multi-purpose finite element analysis (FEA), capable of solving complex problems in the field of Automobile, Aerospace, etc. So LS-DYNA is considered for the study of the B-Pillar simulations. Both the B-pillar designs are accessed and compared with respect to energy absorption, crush resistance characteristics with respect to the full vehicle rollover test. With the detailed performance study of both cross-section designs under rollover impact, the best performing B-pillar design in terms of high energy absorption and high vehicle resistance is selected for furtheroptimization study to meet the Roof crush standard requirements.

Cat Swarm Optimization Algorithm For Antenna Array Synthesis

Cat swarm optimization (CSO) is a developmental technique enlivened by the animals in Mother Nature for taking care of optimization issue. Short of what multi decade after CSO is proposed, it has been improved and applied in various fields by numerous scientists as of late. CSO is created by noticing the practices of cats, and made out of two sub-models, i.e., following mode and looking for mode, which model upon the practices of cats. The prerequisite of high directivity signal with extremely quick pillar guiding is preposterous by a solitary antenna. This imperative is aid by staged array antenna which is a mix of various little antennas that can create shaft with high directivity with quick electronic pillar guiding. The radiation example of an antenna array relies firmly upon the weighting technique and the math of the array. The issues related with pillar design causing high obstruction in communication which confine them use by and by. To beat these im-pediments, optimization innovation called Cat Swarm Optimization are applied in mix with the old style array blend strategies for staged array combination. An optimization issue is determined whose arrangement yields an ideal array for stifling impedance because of high side lobe level and grinding lobe. Results are introduced for ideal arrays of shifting array calculation, with various number of antenna components, and for distinct beamwidths and scan angles.

Rock Pillar Design Using a Masonry Equivalent Numerical Model

In underground mining, the design of rock pillars is of crucial importance as these are structures that allow safe mining by maintaining the stability of the surrounding excavations. Pillar design is often a complex task, as it involves estimating the loads at depths and the strength of the rock mass fabric, which depend on the intact strength of the rock and the shape of the pillar in terms of the aspect ratio (width/height). The design also depends on the number, persistence, orientation, and strength of the discontinuities with respect to the orientation and magnitude of the stresses present. Solutions to this engineering problem are based on one or more of the following approaches: empirical design methods, practical experience, and/or numerical modeling. Based on the similarities between masonry structures and rock mass characteristics, an equivalent approach is proposed as the one commonly used in masonry but applied to rock pillar design. Numerical models using different geometric configurations and state of stresses are carried out using a finite difference numerical approach with an adapted masonry model applied to rocks. The results show the capability of the numerical approach to replicate common types of pillar failure modes and stability thresholds as those observed in practice.