Johannesburg’s early history is the story of gold. In 1853 Pieter Jacob Marais, a South African prospector, recovered alluvial gold from the Jukskei River, north of what would become Johannesburg. The years that followed brought several modest strikes, but the Witwatersrand Main Reef eluded searchers until 1886, when George Harrison, an Australian prospector, chanced upon an outcropping on a farm called Langlaagte. Ironically, Harrison failed to appreciate the significance of his find: he sold his claim for £10 and embarked for the goldfields of the eastern Transvaal region.
Crush pillars are used as part of the stope support in intermediate depth tabular mining stopes. Crush pillar design should ensure that the pillars crush when formed at the mining face. This behaviour of the pillars is typically achieved when the pillars have a width to height ratio of approximately 2:1. Once crushed, the residual stress state of the pillars provides a local support function.
My son Lihan has just turned 2 and every day I am astonished at how he is able to absorb and adapt to his surroundings. Although he is entering the “terrible twos” and verbally expresses his frustration with life, we need to understand that he is struggling between his reliance on us as parents and the desire for independence. At this stage, he absorbs everything said and done around him, and also acts this out. The photograph above was taken at Raka Winery. While I was tasting wine, he was tasting the corks. Whether this was a hint for food or a way of sampling the wine remains a mystery.
In our working environment, we typically form ourselves based on our mentors, managers, their work ethic, and strengths and weaknesses. In some cases, this allows us to thrive and excel in what we do. However, in some areas, mentorship is a luxury and a Rock Engineer could be operating on an isolated operation. As a result, he or she can only rely on his or her own experience and expertise.
On many operations, the design and layout parameters were put in place many years ago and by “respected” Rock Engineers. Consequently, we presume that these designs are correct and cast in stone. However, in this lies a flawed approach. Although these designs were adequate at the time, we have to challenge their continued applicability, based on our knowledge of the environment, new research findings, technology, methodologies and best practices.
I would want to equip my son Lihan with tools which will provide him with the ability to grow and recognise the strengths, weaknesses, limitations and opportunities in every situation. At some stage in his life, he will value the example set by his parents, but will start to mould himself on a new set of criteria, whether it be a role model or his environment. As Rock Engineers, we have the choice to continue to use a copy-and-paste approach (monkey see monkey do) or we can equip ourselves with the necessary tools to ensure that we excel. As Engineers, we should design for purpose, optimise designs and eliminate risk.
37th Technical Evening, 30 June WITS School of Mining New Concept Mining
A very successful technical evening was held by SANIRE’s Gauteng Branch on 30 June 2016 at WITS University’s Digital Mine facility, in conjunction with New Concept Mining. Prof Fred Cawood and his team of postgraduate students facilitated the event in the superb mine design laboratory, which was put together through sponsorship from Anglo American. Two talks were presented; the first talk was by WITS postgrad student, Prince Mulenga (SRK) on coal squat pillar design using numerical modelling, followed by Prof Cawood’s overview of the WITS digital mine facility and of the state of the art in mining technology, as well as of history and a vision for the future.
A Strata Control Mini Symposium was organised and held by the SANIRE Free State Branch at Diggers Inn in Welkom on the 9th June 2016. The day was opened with a keynote address from the SANIRE President, Mr Michael Du Plessis.
The following presentations were presented on the day during two sessions which were led by Dr Jaco Le Roux and Mr Paul Couto: