THE WAY TO GREATER FLEXIBILITY
Many years ago we recognized the need to have flexibility built into the design of coal beneficiation plants.
During its long lifetime a plant will likely encounter widely varying feedstock from different seams and the market requirements for the products will undoubtedly continue to change.
Coal is not a homogeneous substance as it lies in the ground and its uses cover a broad spectrum of industrial applications. In addition to this a significant percentage of the worlds coal production is from smaller operations which have limited reserves and short life spans.
For these reasons we conceived the notion of building plants that are easy to reconfigure or relocate using standard on-highway vehicles as long ago as 1978 and indeed our companys name is derived from this concept. Today we are able to offer plants in a wide variety of configurations and capacities which are fully modular in design from the feed point of the run-of-mine coal to the discharge points of the products and discards. The concept has been so well accepted by the industry over the years that most of the projects that we now carry out are based on this principle and the modules have become highly standardized. This offers major advantages to the clients in many respects but particularly with regard to the speed with which they can be built and commissioned. The capital recovery period for the client is thus greatly reduced and the technical risk is minimized.
The wholly portable modular design, coupled with the very high standards of construction ensures that the plants always maintain their original integrity, no matter how many times they are relocated. This guarantees a high resale value over the long life of the plants. The factory assembled modules, which are free standing and require only simple concrete foundations or slabs as a base, are quick and easy to erect, dismantle, relocate and re-erect and a modular plant can be operational on a new site literally within weeks. They can be shipped and erected anywhere in the world.
FLEXIBILITY IN OPERATING CAPACITY
Single stream plants (i.e. with one drum, one cyclone and one spiral section) have operating capacities up to 350 t/h of raw coal feed, though modules are currently under design which will enable a single stream capacity up to 450 t/h.
There is no capacity limit if the modules are paralleled, making them suitable for a wide range of applications in both small, medium and large mining companies.
It is common to increase the capacity of existing installations by the inclusion of further parallel modules.
DESIGN AND CONSTRUCTION
All aspects of design and construction, including process, mechanical, structural, civil, electrical and piping design, fabrication, transport, erection and commissioning (and ongoing operation when required) are handled with our own "in-house" facilities.
This comprehensive project service results in the shortest possible delivery period and fast, smooth start-up, offering major cost benefits for new processing ventures. All design work since 1994 has been carried out using CAD drawing and design programmes and this has proved an ideal tool for standardized modular design. No two plants are identical and all variations are tracked on a project basis, providing a specific set of drawings and data sheets.
STANDARDS OF CONSTRUCTION
Plate work maintenance is virtually eliminated by the inclusion of abrasion and corrosion resisting materials on all surfaces. The harsh environment encountered in coal washing plants demands the use of the best materials available and the majority of the exposed plate work surfaces are lined with high alumina ceramic tiles of various thickness to suit the application. Only on light abrasion areas and where corrosion only is present do we use epoxy based compounds, rubber, polyurethane and other lighter duty materials.
All surfaces are
suitably lined. High density polyethylene
(HDPE) piping has
proved over the years to be the most suitable material for the fluid transfer operations
in the plants and we now use this material exclusively for all pipe work, thus reducing
failure and maintenance to an absolute minimum. Even clarified water is reticulated in
HDPE pipes. The heavier duty slurry lines are minimum
class 10 piping and sometimes ceramic lined pipe components are installed.
The plants have been developed over the years to be simple to control manually with the minimum amount of instrumentation, thus making them suitable for all companies no matter what their degree of operating sophistication. Numerous features built into the plant operating circuits, permit easy balancing and control.
Automatic density control however is considered mandatory to achieve optimum quality control and in conjunction with instrument suppliers we have developed a highly accurate and reliable nucleonic system based on the absorption of gamma rays through the circulating dense medium and the consequent automatic addition of dilution water. The system is used successfully on most dense medium separation plants today and with proper configuration can maintain densities accurate to the third decimal.
The plants have excellent standards of electrical installation and high lux level internal and external lighting for good night time visibility both on and around the plants. This is of vital importance as almost 50% of monthly production is expected of the night shift.
EASE OF OPERATION
The conceptual designs and practical operating details are well developed over dozens of successful installations and the plants offered are thus well tried and proven. While every plant is different to some extent, there is a high degree of standardization between installations and this guarantees the minimum amount of start up and operating difficulty. Over the years we have refined the designs to make the plants both highly reliable and easy to operate.
In a manually controlled system the electrical motors will be hardwire sequence interlocked and controlled from a pushbutton control desk, which can either be on-plant or located in a nearby control room.
Alternatively the plants are operated from a computer workstation via a PLC and SCADA system (Programmable Logic Controller and System Control and Data Acquisition).
Our engineers are fully conversant with the
design and configuration of such systems and numerous installations are now in successful
While we have concentrated over the years on the South African coal industry and most of our work has been within its borders, we have also demonstrated the feasibility of manufacturing the modular plants in our workshops and shipping them overseas.
We have carried out projects in the United Kingdom and recently we have shipped a 350 t/h modular pre-wet, drum, cyclone and spiral plants with thickener system, filtration system and centrifuge installation to Southern Russia.
Click here "FOR MORE ON COAL PROCESSING PRINCIPLES" - basic theory of coal processing.