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| Preventing falls of ground is
a major challenge at TauTona |
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| Robbie Lazare, General Manager at TauTona, in
South Africa. |
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Case studies
South Africa |
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| 7.1 Facing the challenge of seismicity at TauTona |
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The South Africa region?s TauTona (which means
?mighty lion? in seSotho), is the deepest operating mine in the
world, with mining taking place up to 3,800m underground. And, until
recently this mine, which employs more than 5,000 people and is one
of the largest and most productive operations in the world, also
boasted one of the most impressive underground mining safety track
records. This was until two tragic seismic events ? in April and May
2003 ? resulted in the death of 9 people in two separate incidents.
TauTona was a winner of the AngloGold safety competition (South
Africa Region) in 2000 and 2002. The mine also achieved one million
fatality-free shifts on 28 February 2000 and again on 20 January
2003 ? a feat never before accomplished in the mine?s 42-year
history. The Mine Health and Safety Council (a tripartite body
consisting of government, labour and business) awarded the operation
its Safety Flag, in recognition of superior safety performance
within the South African mining industry in 2000 and 2001.
With a safety performance over the past three years that was
comparable with that of some surface operations, the blows dealt by
the seismic events in the first half of 2003 were all the more
devastating. The first incident, measuring 2.8 on the Richter scale,
occurred on 1 April 2003 on the 111/112 longwall, and resulted in
the loss of five lives and the immediate closure of two stoping
panels. Following investigations, it became apparent that the rock
burst was caused by a seismic event immediately in front of the
mining panels on a fault which had not been predicted or detected by
the mine?s geologists and seismologists.
Then, at 04:08 on 26 May 2003, a seismic event struck the 109 return
airway and replacement haulage which was being developed.
Tragically, four people lost their lives in the incident and both
the return airway and replacement haulage were extensively damaged.
The subsequent rescue operation lasted six days and involved 36
voluntary rescue teams who worked around the clock to recover the
missing miners.
Again, following investigations, the mine plan for the entire area
was reassessed. A detailed investigation into the latter incident
showed that there were in fact two seismic events with magnitudes of
2.8 and 3.0 respectively on the Richter scale. These events occurred
milliseconds apart and once again appear to be related to two
geological faults that traverse the area. It is thought that the
first event triggered the second. The energy that resulted from the
second event, which originated closer to the tunnels than the first,
was transferred into the two development ends where it manifested
itself, causing severe damage.
Says General Manager Robbie Lazare, ?As a result of the incident,
significant expenditure ? about R4 million in 2004 alone ? has been
allocated for drilling long cover holes in the area, to obtain
advance information about the geology well ahead of the face.
Support density and type have also been changed in line with the
most stringent standards ever applied at the mine. Development rates
have also been slowed in areas where the geology is complex.
?Although this has delayed the project by about a year, it will all
be worth it if we can prevent similar accidents in the future.? |
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| On-mine
rescue model |
| Key to any rescue are
the brave proto and rescue team members who perform potentially
high-risk rescue operations in difficult conditions. Together
with Mines Rescue Services (MRS), a volunteer body to which
member mines belong, TauTona is developing a model for on-mine
rescue teams. South African proto teams have traditionally
comprised employees from official level upwards. A pilot is
being run at TauTona mine where all employees are encouraged to
volunteer their services to a rescue team which is trained to
assist in rescue operations, excluding fire and gas, where the
use of self-contained breathing apparatus is required. These
teams are immediately available in the case of an emergency and
are familiar with the mine and its unique challenges. While the
services of MRS can still be called upon if the need arises, the
mine intends being able to cope with most incidents using
trained employees. |
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7.2 Fall of ground management initiative in
South Africa
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In 2003, 78% of fatal accidents on the South
African operations were caused by rockfalls and rockbursts. Of
these, 45% related to rockfalls and 55% to rockbursts. A rockburst
is a seismic release of energy, similar to an earthquake, that
results in obvious damage to mining excavations. The magnitude of a
seismic event is measured on locally calculated magnitude scales,
and can be anything from a minor movement ? which cannot be detected
by an individual ? to a catastrophic event. By reducing the
number of rock-related accidents, a significant number of injuries
and fatalities can be avoided.
Much has been done by the company and the industry by way of
research and development in respect of rock engineering,
particularly in the management of seismicity, strata control,
training and the development of a safety mindset. In fact, through
an internationally-renowned subsidiary company ? ISSI ? AngloGold
applies some of the most advanced and extensive mine seismic
monitoring networks in the world. Although substantial strides were
being made in reducing rock-related injuries and fatalities,
rockfalls and rockbursts remained the main contributors to accident
statistics.
In response to this challenge, the South African Region has devised
and implemented a Fall of Ground Management System (FOGM). FOGM
embodies the manner in which rock engineering is managed to induce
improvements in safety. This system incorporates both proactive and
reactive audits at mine level to evaluate the status of each of five
different elements on a regular basis, and to identify where remedial
action needs to be taken.
The five elements that are audited are: |
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The design of mine layouts. These are
regularly audited by corporate rock engineering personnel. |
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The design of support systems. These are
regularly audited by corporate and mine-based rock engineering
personnel. |
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Human factors involved in falls of ground.
These are tracked by both corporate and on-mine rock engineering
occupational environment, safety and health and training
personnel to ensure that the workforce is equipped with the
relevant knowledge and skills to be able to identify and deal
with hazards. |
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Monitoring systems to verify sufficiency of
designs and implementation. These systems comprise primarily the
extensive seismic networks that are in place on mine. Monitoring
includes in situ measurements, as well as observations of rock
mass behaviour relative to mining activities. |
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Problem solving. This relates to both
company and industry level innovation and technology
development. |
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| Following the development of the system in 2002,
it is now being implemented at all South African underground
operations. Audits, remedial action recommendations and on-mine
implementation are conducted on a continuous basis. |
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Following the tragic accident at Mponeng mine in South
Africa?s North West Province in 1999, the AngloGold Board resolved to set up
the AngloGold Fatal Accident Education Fund to cater for the education of
the children of the victims of all fatal accidents on AngloGold mines. The
implementation of the fund was backdated so that it applied to families
affected since the formation of AngloGold in June 1998.
The Masifunde fund (which in Zulu and Xhosa means ?Let us
learn?) has funded the primary and secondary education of 390 children who
are the dependents of 258 former employees. These children live and attend
school all over South Africa (but mainly in the Eastern Cape, KwaZulu Natal,
Limpopo and North West provinces) and further ? in Lesotho, Botswana,
Mozambique and Swaziland.
AngloGold appointed TEBA, an industry-owned entity with a vast rural and
peri-urban network, to assist with the administration of the fund.
The fund covers the cost of tuition, boarding (where required) and books at
primary and secondary schools. Special arrangements are made where potential
for tertiary education is shown. Although benefits are allocated in an
equitable manner, each case is handled individually and resourced
appropriately according to the specific needs of the various beneficiaries.
Specifically, an assessment is conducted using reports from appropriate
family, union, church, social welfare, education professionals. The
educational institutions utilised need to be appropriate for the needs of
each beneficiary, but bearing in mind the location and circumstances of each
family.
Dependents too old for normal schooling are given access to skills training,
Adult Basic Education and Training (ABET) or appropriate developmental
training and, where suitable and possible, they are offered employment
within AngloGold operations.
In setting up and managing the fund, extensive consultation with union
representatives was conducted. Regular updates are given on the fund and the
children it supports. It is overseen by a management committee comprising
senior AngloGold executives and managers, the TEBA project leader and, by
invitation, two union representatives. |
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