AIB 024*
Manufacturing Sand for the Three
Gorges Dam in China
Case Study
The China Yangtze River Three Gorges Hydropower
Key Project is a mammoth construction project
requiring mammoth resources of sand and aggregate.
A shortage of natural sand in the area, and the high
costs associated with transporting it from elsewhere
prompted the construction corporation to look to
manufacturing sand.
The Solution
Metso Minerals proposed two B9000 Barmac VSI
crushers to produce manufactured sand from a minus
40mm cone crusher product.
Replacing Rod Mills
The two Barmac crushers have been operating
alongside some rod mills, making a manufactured sand
from the hard, abrasive granite. Comparison trials show
that each 440kW Barmac matches the production
capacity of three 220kW rod mills, while wear costs
are reduced to US$0.40 per tonne of sand from the
more expensive US$1.00 per tonne seen in the rod
mills. Trials showed that by utilising the Barmac's
unique cascade system, production of minus 5mm sand
was increased by 7% for no extra power or wear parts
costs
Thus, by installing Barmac crushers in the quaternary
stage, rather than cones, the customer reduced the
number of mills operating.
Conclusions
The Barmac produces a high quality sand which passes
the stringent specifications imposed on manufactured
sand for dam walls and foundations.
Further Business
The need to increase sand production to 1000 tph,
together with the success of the existing machines
has lead to the purchase of a further three B9100
Barmac crushers.
Primary
Gyratory
OSS 130mm
Screen
Sep 1 = 80mm
Sep 2 = 40mm
2 x Barmac B9000 and
3 x B9100 VSI
440kW [600 hp]
840 rotor @ 55 m/s
One on standby
Minus 40
+ 5mm
Screen
Sep 1 = 20mm
Sep 2 = 5mm
Screen
Sep 1 = 20mm
Sep 2 = 5mm
Cone
Crusher
CSS = 40mm
2 Screens
Sep 1 = 5mm
Sep 2 = 3mm
To Sand Screw
3 x Cone
Crushers
CSS = 40mm
Minus 3mm
3-5mm product
to mills
Barmac Models Selected
• Material: Granite
•
•
•
•
•
•
• Feed: Minus 40mm
2 x B9000 Dual Drive Barmac VSI
440kW [600 hp]
Rotor tip speed 55 m/s
840 DTR rotor
20% cascade
Throughput 300 to 350 TPH
•
•
•
•
•
•
• Product: Minus 5mm
3 x B9100 Dual Drive Barmac VSI
440kW [600 hp]
Rotor tip speed 55 m/s
840 DTR rotor
20% cascade
Throughput 300 to 350 TPH
Major Benefits To The Aggregate Industry
With natural sand resources around the world
becoming depleted in some areas and expensive to
process and transport in others, manufactured sand
is fast becoming the preferred option.
An additional benefit of manufactured sand is the lack
of contaminants, such as clay and other deleterious
material.
The Barmac crusher uses a unique rock-on-rock
crushing action which tends to break rock particles
along planes of weakness so that weak, angular
fragments are crushed to produce a high quality
product which is equidimensionnal in shape.
As the material fed into the Barmac grinds and impacts
against itself, the typical wear cost per tonne of
material processed is low.
100
90
80
Barmac Feed
Barmac Prod
Screen U/S
Cum % Passing
70
60
50
40
30
20
10
0
0.01
0.1
1
Sieve Size (mm.)
10
100
Barmac VSI crushers are also used in the industrial minerals, mining, recycling and general quarrying industries. A wide range
of materials are processed through Barmac crushers worldwide. For more information on this or any other Barmac application,
please contact your nearest Barmac representative.
Metso Minerals (Matamata) Limited
Mangawhero Road, Private Bag 4071,
Matamata, New Zealand
Tel. +64 7 881 9060, fax +64 7 888 5244
[email protected]
AIB 024 – 1 – 4/99