Yandicoogina Mine, Pilbara Region WA - Yandi Junction South East Expansion Project - 1500T Surge Bin
In January, 2006 Cardno Buckland provided Calibre Projects with a complete structural solution for the Yandi Junction South East Expansion Project - 1500t Surge Bin and the associated structures in the form of detailed design calculations and design drawings. The scope of the work was to execute the detailed design of the surge bin, its support structure and the concrete footings.
The project was completed on time and enabled the client's schedule of construction date of January 2007 to be met. Calibre projects appreciated the solution offered by Cardno Buckland and their timely completion of the job.
The surge bin had to be designed according to AS3774 and use Grade250 steel for the bin shell. The support steel and other fixtures on the bin structure were designed using Grade300 Australian steel sections.
Oh what a challenge!
The main challenge from a design point of view was that whilst AS3774 provides guidance on calculation of bin wall loads it does not address the design philosophy for bin structures. Other references and advice from in house personnel were sought to complete the design successfully. Two other structural challenges of note were getting suitable bracing between the mechanical components and configuring the main crutch beam.
Space constraints caused by the feed conveyors at the base of the hoppers meant that column bays in the same direction as the conveyors could only be braced in their top half. This meant that the column and the footing had to be designed for the bending moments resulting from curtailed bracing and column base/footing fixity.
The other challenge was to transfer the loads from the bottom hopper half, back to the bin waist through a "crutch" beam. Due to the complex loading pattern and path, two additional columns were introduced under the bin hopper to support the crutch beam. The connections to these columns were made in such a way as to transfer vertical loads only to them and allow all lateral loads to pass to the bracing system on the bin periphery.
Detailed Project Description
Hamersley Iron Pty Limited (Hamersley) own and operate the Yandi Mine in the central Pilbara region of Western Australia. The mine was commissioned in December 1998 and is a conventional open cut iron ore mine in a channel iron deposit. The Yandi Mine is located 90 km north-west of Newman and 300 km south-east of Dampier in the Central Pilbara. The recent extension to the Yandi JC is known as the Yandicoogina Junction South East Project (Yandi JSE). Yandi JSE comprises a new open cut mine in the JSE section of the channel iron deposit to the south east of the current operation associated processing plant and connecting conveyor to the rail load out area.
The 1500t surge bin is part of the new expansion which increases the capacity of the plant to 52Mtpa from the existing 36Mtpa at an estimated cost of US$530Million. The client Calibre Projects contracted Cardno Buckland to carry out the structural design and drafting of the 1500t Bin, the support structure and the concrete footing for it. The main purpose of this bin is to collect the material from the overland conveyor YCV302 and then discharge the material back to the feeder conveyors YFB303 & YFB304. The surge bin is 12m in diameter and has an overall height of 14.285m. It is circular in plan with dual hoppers in the bottom with rectangular discharge openings. The hoppers have complex geometry and comprise curved and chiselled section in the walls. The bin is lined to minimise wear with the lower half of the cylindrical portion lined with rail sections and the hoppers are lined with Dua plate liners.
The bin is supported by six columns and has a stair tower along side for access to the top and to support the incoming feed conveyor.
HPGR Rollers with some Grunt and Grind
Who would have thought that the principle of the "old clothes wringer" would finish up providing the basis of the High Pressure Grinding Rollers, (HPGR) which are frequently and successfully used in the iron ore processing industry in present times.
Weighing upwards from 100 tonnes these machines consist of two horizontal rollers, one fixed and the other floating horizontally under hydraulic pressure, which rotate counter to each other. Ore having passed through primary crushing only is fed from the top into the 'gap' between the rollers and emerges well ground in much smaller pieces. Small is beautiful.
The grinding process sets up vibrations driven by the variation in the feed particle size; hence they are random and according to the roller manufacturers vary between 5 and 15 Hertz. This poses an interesting problem for the structural engineer for the natural frequency(s) of the supporting structure is likely to fall into this range. When this happens the challenge is to ensure that the resulting resonant vibrations do not damage the machine or the structure on which it sits or cause discomfort to the operators. This is essentially achieved by damping down (suppressing) the vibrations by providing sufficient mass in the foundations and embedding them in the ground. This is a technically demanding process requiring a range of soil and foundation data but an area in which Cardno Buckland excel. Therefore, by good design the vibrations are sufficiently suppressed to keep all the faces smiling, the ore grinding and nobody's teeth chattering.
Growing out of the SA sand dunes - Project Magnet
Cardno Buckland has completed the civil structural design and documentation for the concentrator plant at Project Magnet. Promet Engineers and Thiess Pty Ltd commissioned Cardno Buckland to provide detailed engineering design for the civil/structural component of the OneSteel Whyalla project Manet Magnetite Concentrator.
The Cardno Buckland team developed the whole earthworks system, including the lay down area for construction equipment, access roads, ramps and drainage.
The project included two distinct areas, the dry plant, where the ore is reduced to a size suitable for treatment in the flotation plant and the wet plant, which involves further treatment to produce a slurry to be pumped to Whyalla. The dry plant comprises of conveying, raw feed bin (750t live), plant feed bin (750t live), HPGR crushing (2 crushers) and conveyors.
The wet plant consists of a flotation plant, a ball mill, tickeners, tailings disposal system and pumping area. The project has been successfully completed and construction at the site is well under way.
For more background information on this project go to the feature article titled Plant in the SA Dunes.
Pictures courtesy of Thiess and OneSteel
Lifting the Standard for Pilbara Iron's Dampier Port Upgrade
Pilbara Iron Dampier Port Upgrade
In a collaborative undertaking with Monadelphous, Cardno Buckland staff were able to provide valuable assistance to the crew at Transfer Station 18 in the "Stockyard" at Parker Point, Dampier. Monadelphous staff were undertaking the construction and installation of a new and complicated conveyor transfer station for Pilbara Iron.
Pilbara Iron required a simple transfer system to allow ease of transfer from the existing structure to the new one. To minimize downtime the concept was to build the new transfer station along side it's proposed location and when ready, shut down and remove the existing equipment, lift the new structures into place, do final hookup and commissioning and 'turn it on'.
To achieve these lifts the transfer station was divided into four main modules, the heaviest being approx 50 tonnes. Cardno Buckland were able to:
- Design and build structural models from existing shop detailing models.
- Simulate placing each of the four modules on a base frame that was ballasted down with iron ore to withstand cyclonic winds.
- Make sure each module was stable and not overstressed in cyclonic winds or during the lifting process.
- Plan and design rigging, lifting points, padeyes, and temporary bracing to ensure a safe and compliant lift for each module.
- Create shop detail drawings to enable speedy fabrication and installation of bracing components and lifting aides.
Cardno Buckland engineers good planning and creative thinking and precision engineering combined to ensure a result that was safe, expedient and significantly minimised crucial downtime for the client. Efficient team planning and scheduling of the required shutdowns ensured completion without any delays or lost time injuries which gained the praise of the Pilbara Iron project manager.
A Plant in the SA Dunes - OneSteel Magnetite Concentrator Project
Project Overview
In the Middle back Ranges, 60 km south west of Whyalla in South Australia and adjacent the Iron Duke Mine site lies the site for OneSteel's new Magnetite Concentrator Plant.
The project involves the crushing and grinding of Magnetite ore to allow it to be transported in the form of slurry, from the mine site to the plant at Whyalla, a distance of approximately 60km.
The contractor, Thiess is responsible for the design and construction of the plant, retaining ProMet Engineers to provide the process design and the detailed engineering design. Cardno Buckland has provided the civil and structural engineering design for the concentrator plant at the mine site.
The project involves two distinct areas, the dry plant, where the ore is reduced to a size suitable for treatment in the flotation plant, and the wet plant, which involves further treatment to produce a slurry to be pumped to Whyalla.
The dry plant comprises, conveying, raw feed bin (750t live), plant feed bin (750t live), HPGR crushing (2 crushers) and conveyors.
The wet plant consists of a flotation plant, a ball mill, thickeners, tailings disposal system and pumping area.
The plant will use 1500 cubic metres of concrete and 800 tonnes of structural steel.
Earth Works Design Approach
Out of the sand dunes, Cardno Buckland personnel have shaped the earth to provide a working surface on which the plant will be built. Bounded by a railway line on the eastern side, the site required some 500m by 250m of space to accommodate all the processing plant. The dune sand, which covers the site and varies in depth from 1.0m to 3.0m was unsuitable for the foundations and consequently had to be removed. Below this lay several meters of sandy clay, which was quite suitable foundation material and it, is on this that the plant will be built.
The site slopes naturally to the west; the first major embankment ran down from the railway line to a depth of approximately 4.0m and set the level for a major portion of the plant. This embankment (and all others) was set at a slope of one vertically to two horizontally to ensure stability of the slope. With the basic level set for the plant, at the base of the embankment, the site was then graded down the hill at a slope of 1:150 to cater for local run-off.
To accommodate gravity feed for the thickeners a second bench of approximately 5000m2 was cut a further 2.0m deeper in the northwestern corner of the site. Since this bench also catered for a tailings load out Buckland, it was blended into a heavy vehicle haulage road turning circle, the inside of which is to be used for a natural drainage sump.
This was the central concept of the plan on which the Cardno Buckland team developed the whole earthworks system, which expanded to include:
- Lay down area for construction equipment
- Access roads and ramps to site traffic plan for both construction and operating phases
- Major areas of hardstand for all mobile equipment
- Drainage.
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