Barry Woodbine, Schade Lagertechnik GmbH, Germany, celebrates over half a century in stacking and reclaiming.

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1 Schade's history in the design of reclaimers extends back to In 1970, the company supplied the first cantilevered boom reclaimer to a power plant in Germany, now part of the E.ON group, for the continuous recovery of coal for stockpile. Since then, the company has expanded its operations in the coal-fired power plant business, notably within China where 50 huge 120 m dia. circular storage systems have been delivered. However, the power plant is only part of the story. In the last few years, the company has expanded into the mining industry in Australia with some notable successes at both Dawson Creek and Lake Lindsay. Barry Woodbine, Schade Lagertechnik GmbH, Germany, celebrates over half a century in stacking and reclaiming. Figure 1. A Schade stacker operating at the Dawson Creek mining complex in Australia delivers a peak capacity of 4000 tph direct to stockpile, supplied complete with the associated twin boom reclaimer equipment.

2 At present, and for the foreseeable future, the largest market for steam coal is in the Far East, particularly China, driven by the country's insatiable demand for energy. Australia is well placed to satisfy the demand with enormous mineral reserves and excellent deep-water port facilities. For this market, Schade recently delivered some of the largest automated stacker and reclaimer equipment ever produced, with stacking and reclaiming rates of up to 4000 tph, representing cutting-edge chain scraper reclaimer technology. The Dawson project A total of six stackers and six portal reclaimers were ordered for the Dawson project, managed on an Figure 2. Strata stockpile profile created by a slewing and luffing boom stacker. alliance basis by Thiess and Sedgeman. At US$ 350 million, this is the largest contract ever awarded in the Australian coal mining industry and will increase the output of the mine from 7 million to 12 million tpa. Located 140 km to the west of Gladstone, Dawson, one of Queensland s leading export coal operations, is owned by the Moura Joint Venture, comprising Anglo Coal Australia Pty Ltd (51%) and Mitsui Coal Holdings Pty Ltd (49%). The mine is operated by Anglo Coal Australia. Coal is delivered to the new facility from three separate mining resources by a system of overland belt conveyors to the raw coal stacker and reclaiming system, designed by the company, with a design handling rate of some 4000 tph/unit and a longitudinal stockpile capacity of some 200,000 t. Figure 3. Luffing boom stacker used to generate Chevron profile stockpile for blending. After processing, the coal is stocked out by another Schade boom system to stockpiles with 270,000 t capacity, using travelling stackers operating in windrow mode. Reclaimers similar to the raw coal section automatically recover the processed coal from the product stockpiles, which is then transferred to automated train loadout stations able to load the 7300 t coal trains in two hours. With a rail span of 52 m, these are not the widest machines the company has produced (65 m), but the combination of handling rate and span makes this equipment the largest and most important contract that it has undertaken. To achieve such high reclaim rates, now approaching 4000 tph, it is necessary to use a twin boom arrangement with two identical scraper booms mounted to a common portal frame. The company were the first to introduce this concept back in around Since then, the equipment has developed considerably, but the fundamental problems of coal stockpiling, stockpile management and output quality control remain very much the same. The client demands reliable quality with high repeatability and full homogeneity throughout the consignment. Whether this is in a railcar of 60 t or a capesize bulk carrier of 180,000 t, the demands are exactly the same: only the scale changes. Stockpiles and blending beds These demands are also the same for the power plant. In the early days of automated coal stockyard engineering, Schade, located in the middle of one of the most important coal-producing and consuming areas in the world at that time, developed concepts in the Ruhr valley power plants that remain valid today at the minesites. Coal is brought into the power plant or, for a minesite, to the central processing area and discharged to discrete strategic stockpiles. Each generally represents a specific quality or source from which the final output of the mine will be blended. For the strategic stockpiles, a radial and luffing stacker is often provided, 58 WorldCoal November2009

3 allowing 180 boom rotation such that the stacker may service two parallel stockpiles from a single central incoming conveyor and tripper unit, all mounted to common rails between the two stockpile runs. Using a slewing and luffing stacker, the stockpile may be managed to provide effective blending of the incoming coal such that moderately dissimilar materials may be effectively blended by laying down the stockpile in the strata form (Figure 2). In this manner, the stockpile is generated by the continuously travelling stacker moving back and forth along the designated operating zone with small vertical height and horizontal displacement increments after each pass. Using the strata system, thin layers are projected to the inclined stockpile face and each layer may contain dissimilar materials, making the whole stockpile a series of discrete sections represented by the different colours in Figure 2. When the portal reclaimer boom scrapes the stockpile face, it takes elements from every layer, and thus the resultant Figure 5. Circular storage with luffing boom stacker and bridge reclaimer for homogenised output. output material is an effective blend of the range of coal qualities found in the stockpile. Obviously, the degree of blending is determined wholly by the management of the stacker and, once the stockpile is laid down, it is impossible to change the composition of the output. For this reason, most coal processing plants where a range of materials are to be blended will combine both strategic stockpiles and blending beds such that the final output may be regulated and changed to suit the client demand or contract specification. The coal is recovered from the strategic stockpiles by a conventional Schade portal reclaimer and transferred to blending beds where it may be homogenised and the final output quality controlled. At the blending beds, a travelling and luffing boom stacker (Figure 3) is employed to deposit the material moving continuously along the length Figure 4. Chevron stockpile profile for blending beds using a bridge reclaimer for homogenised output. of the stockpile, generating layers incrementally (Figure 4). The machines illustrated are supplied with a boom length of 31.5 m and have a design stacking rate of 1800 tph. The stockpile illustrated in Figure 4 is known as the Chevron method due to the shape of the individual layers. By laying down thin individual layers along the full working stockpile length, the section of the stockpile will comprise slices of every material type and, when recovered across the full stockpile section, the output flow comprises elements of each layer and is fully homogenised. Coal may be loaded to the blending beds from different discrete stockpiles of varying quality, each of which may be preblended using the strata system as already described. Stacker and reclaimer The bridge reclaimer comprises a standard chain scraper boom, but mounted horizontally with each end supported to individual rail bogies. To encourage the coal to flow from the stockpile to the reclaimer, conveyor reciprocating harrows are employed and aligned to the material repose angle. Fitted with sharpened steel tines at intervals across the full harrow width, as the harrow reciprocates the coal is dislodged and flows down under gravity. The bridge reclaimer scraper conveyor shows the deflected discharge section, allowing material to be raised up to the stockyard belt at the same level as the reclaimer rails, thus eliminating any complex civil works and simplifying the stockpile bed construction. The management of the stacker and reclaimer is critical for the effective performance of the system as a whole. For this purpose, Schade has developed software routines to ensure proper operation of the stacker to generate a homogenised bed and to ensure the stacker and reclaimer operating zones do not conflict. In addition to conventional longitudinal blending bed designs, the company also offers bridge style reclaimers in the circular format (Figure 5). The concept is identical to the longitudinal designs, except that the stockpile must be wrapped around the November2009 WorldCoal 59

4 central column. In this case, the bridge reclaimer discharges through the stockpile centre, much the same as the conventional circular storage systems previously described. Such a system is easily enclosed within a dome structure, giving complete environmental protection, eliminating wind blown fugitive dust pollution and improving aesthetics in environmentally sensitive locations. These circular storages and blending systems offer the most economical solution with the minimum footprint and a controlled environment, eliminating contaminated water run-off causing ground pollution, often a major issue in areas of high rainfall or close to harbours, rivers or aquifers. Lake Lindsay project In addition to the Dawson project, the company has recently been awarded a further contract of similar scale for the Lake Lindsay development, including three reclaimers and two stackers. Representing a tremendous boost to the local economy, the Anglo Coal Australia development of the proposed Lake Lindsay open cut coal mine, adjoining its German Creek operations in central Queensland, is owned jointly by Anglo Coal Australia (70%) and Mitsui Coal Holdings (30%), representing a major investment and creating substantial economic benefit for Queensland. The mine s saleable production will be 4 million tpa, comprised almost entirely of valuable met coal used in the production of steel. Lake Lindsay is an important part of Anglo Coal Australia s growth strategy to increase total managed coal production from all mines to 50 million tpa and demonstrates the company s confidence in the long-term market. Schade are supplying the key machinery for the coal stockpiling and recovery. As always, attention to detail is critical to obtain performance and reliability. As illustrated in Figure 6, the Schade lateral guidance system is based on opposing guide wheels running on the rail edge, supported on vertical axles such that the two sets of Figure 6. Travel bogie for bridge reclaimer showing lateral guidance wheels. Figure 7. Portal reclaimer showing boom guidance system to absorb lateral forces from the scraper conveyor. Figure 8. Portal reclaimer with upswept deflected boom and conveying trough to raise the discharge level. 60 WorldCoal November2009

5 Figure 9. Bridge reclaimer rebuilt and upgraded from 1200 to 1800 tph reclaim rate. guide units control the relative alignment of the reclaimer. In this manner, the machine is guaranteed to remain at 90 to the rails, and the horizontal forces generated by scraping the material to the edge of the stockpile are transferred effectively through to the rail. Figure 7 shows a typical arrangement for a larger portal reclaimer with single boom design, showing the travel bogie on the side opposite to the discharge. On this side of the machine, the bogie is mounted to a hinge pin fixed to the portal frame, allowing for minor relative misalignment of the rails and accommodating thermal movement of the structure as well as design deflection under varying loads. This illustration also shows the boom guide developed by Schade to absorb the horizontal loads applied to the boom structure as the machine recovers the material, working along the length of the stockpile. These loads are transferred from the boom head and tail sections to the portal frame, resisting any twisting load applied to the chain scraper conveyor boom itself. The discharge side of the reclaimer (Figure 8, pictured from the centre of the stockpile), shows the travel bogie and the raised upswept discharge output trough arrangement of the scraper boom, allowing the coal to be raised up to the collecting conveyor on the same level as the rails. The bogie on the discharge side includes not only the travel drive and lateral alignment rollers, but generally also supports the control equipment and the operators cabin. Whilst the equipment will recover the coal automatically from the desired operating zone, it is necessary for the operator to first trim the stockpile, controlling the boom and travel gear manually to even the stockpile level before switching to automated operation. Once switched to automatic, the equipment may operate unattended. Commitment to excellence The company was one of the first in the field of chain scraper reclaimer designs and now has over 600 units in the market, covering a complete range of applications from small semi-portal designs through to huge stacking and reclaim systems for minesites as described herein. Schade, now part of the Aumund Group, is continually pushing the design boundaries and is not far away from breaking present records with rail spans increased to over 70 m and handling rates breaking the 4000 tph barrier. Naturally, performance and quality are paramount in this industry, but economy and efficiency in design and construction are also critical in today's price conscious market. Responding to these pressures, Schade has adopted the Aumund Group business model, combining German engineering standards with the least cost manufacturing locations, commensurate with effective quality control. The after sales and support network has been expanded to improve customer support and access to genuine Schade spare parts. Naturally, all mechanical equipment, however well engineered, has a finite lifetime and the company offer comprehensive support for rebuilding and upgrading the existing machines and equipment, even if not originally built by the company. Typically, as illustrated in Figure 9, a bridge reclaimer installed at W.D.T. Curragh in Australia for blending coal was rebuilt and upgraded from 1200 to 1800 tph, including new chains, sprockets, scraper-shovels, wear strips and chain drive unit. However, the existing frame was reused and at a fraction of the cost and disruption of a complete replacement. November2009 WorldCoal 61