User:MacGuire Roughley/sandbox

New References
https://doi.org/10.1007/s00024-015-1033-x

Mining-Induced Stress Transfer and Its Relation to a  1.9 Seismic Event in an Ultra-deep South African Gold Mine.

- ultra-deep tabular mining environment

- located in the north-western of the Witwatersrand Basin, SA (Centre of Kaapvaal Craton). known as one of largest gold mining districts.

https://doi.org/10.1785/0120000226

- Induced seismicity associated with five deep gold mines located in the far west rand district

-Exceeds 1000 events per day

-Type A – are tightly clustered in time and space and generally occur within 100m of an active mining face or development tunnel with moment magnitude <1. Induced by dynamic stresses during blasting and quasi-static stress perturbations from excavation and closure of individual stopes.

- Type B – temporally and spatially distributed throughout the active mining region, they represent friction-dominated slip in existing shear zones. Possible >3 but lower cutoff of roughly 0

-Mines create great sites for study,

-Type A typical after blasting.

-Type B from slip-weakening, analogous to tectonic earthquakes

https://doi.org/10.3997/2214-4609.20140511

-      The Witwatersrand basin (South Africa) holds some of the world’s largest gold reserves, having produced over 1.5 billion ounces.

-      This 3D seismic survey was aimed at imaging the key economic gold-bearing reefs or conglomerate units such as the Ventersdorp Contact Reef (VCR ~ 1.5 m thick) and Carbon Leader Reef (CLR ~ 1 m thick). The 3D seismic design, acquisition and re-processing are summarized by Manzi et al. (2012).

-      The AngloGold Ashanti currently aims at using their historical 3D seismic data to assess the feasibility of their deepening world’s deepest gold mine (Mponeng Gold Mine) in order to give access to additional reserves below 4 km in depth

-      The Mponeng Mine exploits the VCR at depths between 2400 and 3900 m below the surface, whereas the CLR is exploited at depths up to 4 km below the surface (Figure 1).

-      The ghost-CLR model, in particular, may reduce risks associated with deep mining in Mponeng Gold Mine and increase efficiency and safety

https://doi.org/10.1007/s00024-015-1033-x\

-The Mponeng Gold Mine represents a typical ultra-deep tabular mining environment and located in the north-western part of the Witwatersrand Basin, South Africa

-The analysis of the modelled stress state, immediately before the seismic event, strongly indicates that stress changes due to mining excavations induced this event (On 27 December 2007, a 1.9 seismic event occurred within a dyke in the deep-level Mponeng Gold Mine, South Africa).

Vegter, Ivo (2018). "Why Mining Still Matters". South Africa Institute of Race Relations 2018: 11

- mining SA has been pioneering, changing technology, leading world. techniques that have been used world wide.