Mining_Methods_UnderGround_Mining - Mining and Blasting

el TenienTe, CHile
Undercut drilling to start the caving process.
According to Atlas Copco Chilena,
which delivered the equipment, the
Rocket Boomer units exceeded the ma-
nagement's expectations, and showed
better results in comparison with the
other rigs owned by the mine. For instance,
in the development of 4 m x 4
m drifts, where each round required a
total of 48 drill holes of 45 mm and two
cut holes of 4 in-diameter, the Rocket
Boomer rigs drilled holes 4.0 m-long,
whereas the other rigs drilled holes 3.1
m-long. The Rocket Boomer rigs also
surpassed the older drill rigs in penetration
rate (1.9 - 2.0 m/min vs 1.23 - 1.28
m/min), drill m/effective hour (150 vs
77.5), drill m per round (200 vs 155),
drilling time per round/min (85 vs 155)
and advance rounds/shifts (3 vs 1.0 - 1.5).
Maintenance programme
Today, in terms of maintenance, El Ten-
iente is close to being self-sufficient, and
does most of its own work. Maintenance
programmes for all the units are based
on the suppliers' information, plus experience
gained in use. All this data is
held on a centralized system that moni-
tors all machines, checks when they need
maintenance, and organizes what spares
will be required. There are centralized
maintenance workshops for drill rigs,
LHDs and utility vehicles, with one
major workshop for each machine type.
In this way, the maintenance department
and its team provide a central technical
and maintenance service to all the sec-
tors within El Teniente. Smaller
workshops dispersed throughout the
complex are used for repair or maintenance
jobs of less than four hours
duration. Major rebuilds and repairs
are handled at the central workshops
on surface, one for component rebuilds,
and the other for major machine overhauls.
Atlas Copco maintains a team of
technicians permanently at the mine,
working with the maintenance department
on the commissioning of new
equipment, and providing support and
operator training during the warranty
period of the units.
recent developments
Framed within Codelco's current US$4.2
billion strategic plan, the US$1.1 billion
Plan de Desarrollo Teniente (PDT) is the
great mining, technical and management
strategic plan of El Teniente Division
for the next 25 years. Its objective is to
expand the production capacity at all
levels, including mine, concentrator,
smelter, hydrometallurgy and services,
and increase El Teniente's economic
value by over 90% from US$2 billion to
US$3.8 billion.
Amongst other things, the plan contemplates
the incorporation of worldclass
technology.
Occupying an area of 190,000 sq m,
Reservas Norte/Sector Andesita is lo-
cated north of the Teniente Sub-6
sector. Its reserves are estimated to be
125 million t, with an average grade
of 1.14% copper. Its useful life will
last until 2019, and during operation it
will require a workforce of 280 people.
Construction was started in 2000 for
production commencement in 2003.
Production is planned to reach 35,000 t/
day and, like Esmeralda, Reservas Norte
is being exploited by panel caving with
the pre-undercut variant. Main equipment
includes 14 LHDs of 7 cu yd capacity,
16 plate feeders, eight 80t trucks,
four hydraulic breakers, and five 1,400
HP fans. On the production level, the
LHDs tip into 34 m-long orepasses.
On the haulage level, the 80t trucks,
loaded by plate feeders, empty the mineral
into four storage bins fitted with
large hydraulic breakers and grizzlies.
One of the objectives of this project
was to automate and remotely control
the operations of truck haulage, plate
feeder loading, and rock reduction by
breakers.
With an area of 57,600 sq m, Pipa
Norte is located north of the Braden pipe
and south of the Quebrada Teniente
sector. Its reserves are estimated to be
27.1 million t, with an average copper
grade of 1.024%. Construction started
in 2001 for production commencement
in 2003, with a peak rate of 10,000 t/day
by 2005 and a useful life of 10 years.
The exploitation method is panel caving
with pre-undercut and low excavation,
with a labour force of 43 people and a
planned personal average productivity
rate of 220 t/day. 13 cu yd capacity die-
sel LHDs are part of a semi-automated
loading operation, with an operator on
surface remotely controlling three loaders.
LHD transport and unloading is
fully automated.
Located south of the Braden pipe,
Diablo Regimiento takes up an area
of 201,200 sq m. Its reserves include
98.9 million t, with an average grade of
0.94% of copper. Construction started
in 2001 for commencement of production
in 2004, aiming at 28,000 t/day by
2011 with a planned life of 16 years.
Average productivity is estimated to be
230 t/day, with a peak labour force of
115 people. The exploitation method
88 underground mining methods