ProjectsTHE BASIL READ GROUP

Mining and processing activities in Zimbabwe and some thoughts on mining

the Great Dyke.

Dr Michael Roberts, TWP

SAIMM Zimbabwe Branch May 2010

Who are we?

Basil Read

Construction

Buildings

Roads

Civils

Mining Developments Engineering

Basil Read Engineering

TWP

Who are we?

A generic description of some project work undertaken in Zimbabwe by TWP.

What do we do?

Pickstone-Peerless hydrothermal gold deposits.

Activity

Location

Pickstone-Peerless hydrothermal gold deposits.

A plant will be built on site to treat a sulphide dump. Later there might be consideration given to going underground.

Activity

Unki declines on the Great Dyke.

Activity

Activity

Unki declines on the Great Dyke.

Declines completed.

Activity

Activity

Evaluating and assisting with respect to efficient Chrome mining associated with the Great Dyke.

Activity

Optimise mining and process engineering on the Great dyke with respect to Platinum groupelements.

How done.

Optimise mineralogy, mining and process engineering by recognising that the ore body is not homogeneous.

The Bushveld complex

The Great dyke

There might be some commonality with respect to structure in the Bushveld and the Great Dyke.

Mining on the Bushveld and Great dyke

Easy mining on the Great Dyke

Easy mining on the great dyke

Easy mining on the Great Dyke

Easy mining on the Bushveld

Difficult mining on the great dyke

Difficult mining in the Bushveld

Some commonality with respect to structurein the Bushveld and the Great Dyke.

Flexural slip thrust faults.

Great dyke

Flexural slip thrust fault

What is a flexural slip thrust fault?

Ore body

SectionFlexural sl

ip thrust f

ault

Flat

Flat

Ram

p

Flexural slip thrust fault

FlatRam

p

Flexural slip thrust fault on the Great Dyke ?????

Flexural slip thrust fault - origins

Flexural slip thrust fault - origins

Flexural slip thrust fault - origins

Flexural slip thrust fault - origin

Scientific description of a flexural slip thrust fault

Part of the Platmine Research Programme funded by: Anglo PlatinumImpala PlatinumLonmin

Peer reviewed scientific paper referenced:

S. Perritt and M.K.C. Roberts “Flexural-slip structures in the Bushveld Complex, South Africa?”Journal of Structural Geology, Volume 29, Issue 9, September 2007, Pages 1422-1429.

S. Perritt and M.K.C. Roberts “Flexural-slip structures in the Bushveld Complex, South Africa?”Journal of Structural Geology, Volume 29, Issue 9, September 2007, Pages 1422-1429.

S. Perritt and M.K.C. Roberts “Flexural-slip structures in the Bushveld Complex, South Africa?”Journal of Structural Geology, Volume 29, Issue 9, September 2007, Pages 1422-1429.

Fall of ground fatalities over a set period

Curved joint moved as a precursor to fall of ground

Thrust fault or curved joint directly fell on deceased

Seismic causes

Other reasons for fall of ground

9/32 15/32 2/32 6/32

Breakdown as to cause of 32 fall of ground fatalities

Pillar failure due to gouge on flexural slip thrust fault

Pillar failure due to gouge on flexural slip thrust fault

Gouge

Pillar failure due to gouge on flexural slip thrust fault

Understanding the structures

• Understanding geological structures within the ore body.

• Rock mass ratings.• Rock strengths

• Mining method. • Appropriate mining span• Excavation support

Structural geology Rock engineering Mining engineering

Knowledge gap

Understanding the structures

• Understanding geological structures within the ore body.

• Rock mass ratings.• Rock strengths

• Mining method. • Appropriate mining span• Excavation support

Structural geology Rock engineering Mining engineering

Knowledge gap

Expect surprises and production disruptions

Understanding the structures

• Understanding geological structures within the ore body.

• Rock mass ratings.• Rock strengths

• Mining method. • Appropriate mining span• Excavation support

Structural geology Rock engineering Mining engineering

Expect smoother production profile

No knowledge gap

TWP Plant Design Example

Thank you