ORE SORTING AND GRAVITY_proof 27/04/2016 09:59 Page 1
ORE SORTING AND GRAVITY
allmineral allair type
MP plant in Indian
coal preparation
Good ore bad?
Ore sorting has been one of the most important developments in recent years in mineral processing –
expanding the use of high-tech sensors aimed at pre-concentration of ore. The most common sensors
are colour sensors with Charge – Coupled Devices (CCD cameras). These allow use of the RGB
colorimetric system to separate minerals of different hues, and in many cases, a difference in brightness
he more recent development of the use of
dual energy X-ray transmission (DE-XRT)
Dual Zone allows separation by atomic
density of the mineral constituents of the rock.
The great economic potential of ore sorting is
well demonstrated by the example of CRC ORE
investigating grade engineering strategic
options for a copper/molybdenum operation. A
detailed project plan was developed covering
characterisation, spatial modelling, process
modelling and value quantification. The program
comprised detailed grade by size testing at
variability and bulk scale as well as detailed
blast design for induced metal deportment.
The results were used for the design of a
grade engineering pre-concentration circuit and
subsequent mine planning and scheduling
activities. The benefits identified were:
n Change in NPV of >$400 million in current pit
n Increased net cash flow of $1.3 billion in first
20 years
n Additional 480,000 t of copper in first 20
years
n Increase in feed grade to the concentrator of
6.4% and 2.9% for Cu and Mo respectively
T
18 International Mining | MAY 2016
n Grade engineering payback period <2 years.
Sorting and screening
AKW Equipment + Process Design’s AKA-FLOW
is a dry operation gravimetric sorting device
used for preliminary separation and
enrichment of materials of different densities
as a possible pre-stage to wet mechanical
separation processes. Limited availability of
water in arid areas requires additions to the
wet mechanical processing technology. Dry
gravity separation ensures, amongst other
Principles of operation of the AKA-FLOW