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definition of flat tabular reef in gold mining

The unit "m 2 /month" is typically used as a measure of "volume" of mining as the mined reefs are flat dipping tabular orebodies. The typical mining height varies between 1 and m. The area …

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Zondereinde Mine

The UG2 reef comprises three layers of chromitite that are separated by a 15cm thick pyroxenite. The primary member is approximately 80cm thick while the other leading members are on an average 20cm thick. Mining. Typical drill and blast narrow tabular reef mining techniques are used at Zondereinde underground mining.

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GOOD LEDGING PRACTICE

Historically the mining of hard rock narrow tabular reef bodies has been carried out by employing conventional stoping methodologies which rely on ledging as one of the initial operations. The reef is accessed by way of shafts, inclined accesses or addits, and tunnels are then driven (mainly in the footwall) to access the reef.

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Optimization of cut-off grades considering grade uncertainty …

South African tabular-reef gold mines are deep and subject to highly variable gold grade distributions (Sichel, Kleingeld, and Assibey-Bonsu, 1992). Even with high-quality sampling, there are differences found between the estimated grades for mining blocks (used for planning purposes) and the actual values (which determine revenue from a block).

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Reef Boring Technology

To accurately drill and ream holes on reef in narrow tabular ore bodies typically found in the South African Gold and Platinum mines. ... By doing it this way there is no need for the blasting of rock with explosives which means that mining can take place 24/7. People are not exposed to high risk areas (on the face) and roof support and scraper ...

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Remnant Mining in South African Gold Mines

A simulated rockburst was conducted underground at Kopanang Mine, previously called Vaal Reefs No. 9 Shaft. The rockburst was simulated by means of a large blast detonated in solid rock close to a ...

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Grade and geological continuity in high-nugget effect …

2 Mineable grades within gold-quartz reefs are generally concentrated in high-grade oreshoots. This scenario, based on a North American mine, shows a series of plunging shoots within a reef.

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Optimizing the cut-off grade for tabular gold deposits, …

South African gold mines exploiting narrow tabular reefs face high mining costs, making many of them marginal. The associated mineral resource royalty costs significantly influence the conversion of Mineral Resources to Mineral Reserves when applying an economic cut-off grade (Lomberg and Rupprecht, 2017). Mining

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Basic principles for stable gullies in the gold and …

way in which tabular reefs were mined, and stope gullies with scrapers were in use across the industry. This access layout is less prone to stress and rockburst damage, while scrapers in smaller on-reef excavations improved mining efficiency. During the 1980s, some mines introduced trackless Load-haul-dump (LHD) cleaning equipment,

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A Robot Miner for Low Grade Narrow Tabular Ore …

economic at mining heights of greater than 80 cm. The Middelvlei reef is used as an example. In Figure 2, it can be seen that any mining system capable of economically mining reefs at a stoping width of less than 0.5 m significantly increases the reserves from …

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Rockburst support in shallow-dipping tabular stopes at …

date more than 50 000 tons of gold has been mined from this basin14. After more than 100 years of mining, most of the remaining orebody is located at great depth (3 - 4 km depths in some mines). The associated rockbursts and the difficulty of providing adequate ventilation are two of the key engineering challenges when mining at these great depths.

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African Rainbow Minerals crowns grade as king, declares war on reef

"I grew up in the industry in gold and platinum mining, and we know that the platinum and narrow tabular gold seams in South Africa are, in general, 60 cm and less, and the containment within ...

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TWENTY FIVE YEARS OF MECHANISATION OF TABULAR …

The Background to the Start of Mechanised Mining of Tabular Reefs on the Gold Mines of Johannesburg Consolidated Investment Company. 21 . 2.1 Early Background 25 . 2.2 Arguments for Wide Reef Mechanisation at Cooke 2 Shaft, REGM. 27 . …

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Geological factors influencing the design of a narrow …

Why autonomous mining? How? Quartz-rich Tough! Geological factors play an important role in the design of any autonomous narrow-reef miner in South Africa. Thank you. Questions?

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Numerical Simulation of a Multi-Reef Tabular Mining …

upper Merensky reef (a pegmatiodal pyroxenite) and the lower UG2 reef (a chromitite layer). Both reefs are tabular in nature with a small dip (9 to 18 ). The stoping width on both reefs typically varies from 1.1 to 1.5 m. Based on the economic importance of these mining activities to South Africa, it is vital that

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TWENTY FIVE YEARS OF MECHANISATION OF TABULAR …

Chapter 1: Twenty Five Years of Mechanisation of Tabular Orebodies in South African Gold and Platinum Mines. 1. Introduction . Chapter 2: The Background to the Start of Mechanised Mining …

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Presidential Address: The mechanisation of UG2 mining …

narrow tabular orebody mining method for which South Africa is famous. It is, and has been, widely practised throughout the industry in gold, Merensky reef, chrome reefs, and the UG2. The main advantage of conventional mining is that access to the orebody is in the footwall, so the development, waste can be hoisted separately from the reef.

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A hard rock narrow reef mining machine—ARM 1100

based mining to that of continuous non-explosive mining methods has been the dream of many mining engineers. Much of the vast Bushveld Complex has favourable dipping orebodies, mostly in the range of 8 to 13°. This, when compared to the steeply dipping orebodies of the South African gold mines, the bushveld invites the potential

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Ideal stope profile to manage seismicity in deep …

Deep Mining 2019 Conference Muldersdrift, 24–25 June 2019 The Southern African Institute of Mining and Metallurgy 293 Ideal stope profile to manage seismicity in deep tabular narrow reef mines O. Rakumakoe AngloGold Ashanti, South Africa More regional stability pillars have been introduced in deep narrow reef mining stope

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Mechanization in stoping narrow tabular orebodies

Mechanization in stoping narrow tabular orebodies Initial practice at Northam Due to the geological structure of the Platiniferous reefs in the Northam lease area, a scattered mining approach was selected with breast mining layout for the stoping panels. Typical panel length is in the region of 25 metres. The geothermal gradient of the Bushveld ...

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The nature and origin of the Merensky Reef of the …

ally all platinum mining up to about the mid seventies took place on the Merensky Reef of the western Bushveld Com­ plex. The reef has been traced for over 145 km, with current underground stoping and shallow opencast extraction taking place over a strike distance of some 80 km, mainly in the western lobe (Figure 1).

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Technical operating flexibility in the analysis of mine …

Definition of operating flexibility The New Collins Dictionary and Thesaurus(1989, p. 382) ... different mining methods to (incl. cooling & refrigeration); geological features and allows for selective mining. mine ultra-deep tabular gold reefs. rock engineering stability; logistics; LOM. LSP not flexible for negotiating geological

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afecting mining-induced seismicity in a deep tabular mine

The ournal of the Southern African Institute of Mining and Metallurgy VOLM MARCH 2022 115 A case study of geotechnical conditions affecting mining-induced seismicity in a deep tabular mine by L. Scheepers1 and D.F. Malan1 Synopsis Seismic risk in the deep gold mines of South Africa has been studied for many decades. A clear

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Chapter 2. BASIC MINING IN.FORMATI·ON

At this point it is important to understand that, for mining purposes, the reef plane is defined in terms of true dip, width and position relative to a grid on the surface of the earth (and a specific …

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Conventional narrow tabular

The conventional narrow tabular mining methods mostly include conventional breast mining, up dip mining, downdip mining and several variations thereof. Access to the reefs and ore bodies …

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Continuity Risk in Narrow Reef Gold Deposits

Narrow reef gold deposits are generally less than 4 m in width and relatively complex geological phenomena. They often display variable geometry, attitude, continuity and internal architecture. Economic grades are mostly restricted to specific structural domain(s) and localised within discrete ore shoots that have a nuggety internal grade distribution. On account of the often …

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Microsoft PowerPoint

Tabular deposits Flat - <350 dip Wide Reef – Bord and Pillar, Drift and fill Considerations: • Span between pillars • Fill material availability • Subsidence • Geological weaknesses particularly jointing, potholes, triplets, smectites, etc • Depth relatively shallow

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The design and development of an effective support …

support system for tabular stopes in gold and platinum mines A. Daehnke, M.K.C. Roberts, M. van Zyl, E. Acheampong & G. Harper 1 R. Ottermann, D. Burger & A. von Wielligh 2 Research agencies: CSIR: Division of Mining Technology 1

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Numerical Simulation of a Multi-Reef Tabular Mining …

Two reefs are currently of economic importance namely the upper Merensky reef (a pegmatiodal pyroxenite) and the lower UG2 reef (a chromitite layer). Both reefs are tabular in nature with a …

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A case study of geotechnical conditions affecting mining …

The stable and safe mining of deep tabular excavations is an ongoing problem of considerable technical and economic interest requiring an understanding of the interactions between local rock ...