This invention relates to improvements in ore screening decks used in the separation and grading of materials in the mining and quarrying industries. In particular it is concerned with improving the useful life of screen decks before wear of the panels, caused by impacts and abrasion in the screening process,

necessitates the replacement of the panels.

Australian patent 482212 proposed a modular screening panel system for ore screening decks which is now widely used by the mining industry and replaced the earlier screening cloths, and large wire screening frames. The screening panels were all of the same size and made of reinforced polyurethane. The panels are adapted to be secured to an underlying support frame using dependent spigots which are a force fit into corresponding apertures in the support frame. Australian Patent 517319 provided an alternative method of securing the panels to the frame using a pin expanded fastening concept.

The Australian patent 556953 disclosed the use of a hold down bar which abutted the edge flanges on the panels and had spigots passing through apertures in the edge flanges and into apertures in the underlying support frame. Australian patent 700843 disclosed a two part hold down bar the first being bolted to the frame and the second being a snap fit into the first part.

Hard grades of rubber and polyurethane are conventionally used as the material for the screening panels usually reinforced with steel. These panels wear away and need to be replaced from time to time. The down time for maintenance impacts on the productivity of the mine as well as involving the labour and material cost of the actual removal of warn panels and installation of new panels. The section of the deck that is most subject to wear is the initial feed zone of the deck where the panels are often blank and do not incorporate screening apertures.

It is an object of this invention to extend the working life of a screen deck before the panels need replacement To this end the present invention provides a modular panel for a screening deck which includes an impact surface of an alumina ceramic which is bonded to a metal support.

The wear and abrasion resistance of the panels of this invention is superior to that of conventional polyurethane and rubber panels. Preferably the alumina ceramic tiles are bonded with adhesive to a steel base. The adhesive may be any suitable adhesive such as epoxy based resins. In order to achieve a robust bond of the alumina ceramic tile to the steel substrate the panel is subjected to a vacuum and then the adhesive is allowed to cure by heating or other suitable method. The vacuum bonded alumina ceramic steel panel is able to resist high impact and abrasion. The vacuum bonding prevents tile failure and breakaway during impact. The alumina ceramic is known to have a high resistance to abrasion but like all ceramics is not particularly resilient or flexible.

The panels of this invention are suited for the feed zone of the screen deck where the panels may be blank and not have apertures. The panels of this invention are also suitable for screening. When panels need apertures, the apertures may be laser cut into the bonded ceramic and/or the vacuum bonded panels after manufacture.

The panels are preferably installed onto the screen deck using clamping bars that grip the parallel edges of the panels.

A preferred embodiment of the invention will now be described with reference to the drawings in which

Figure 1 is an exploded view of the feed section of a screening deck;

Figure 2 is an isometric view of an installed feed section of a screening deck.

The modular panels 10 of this invention are alumina ceramic tiles vacuum bonded to a steel base. The base is preferably a steel plate and the alumina ceramic tiles are bonded to the base using the Thermo vac™ method of vacuum bonding. These panels 10 are blank as they are intended for use in the initial feed section of the screening deck which is subject to highest impact and abrasion loads.

The panels are mounted to the machine frame 12 using a clamping system. The clamping system consists of the support bars 13, the bolts 15 and the clamping plate 20. The support bars 13 seat on the machine frame 12. Bolts 15 extend through holes in the machine frame 12 and the support bars 13. The bolts are protected from abrasion by the angle bar 14 which seats under the flange of machine frame 12 to cover the end of the bolts 15.

The clamping plates 20 are adapted to seat on the support bar 13 so that the edges of the plate overly the edges of the panels 10. On clamping plate 20 the nuts 22 are adapted to engage the end of the bolts 15 to secure the clamping structure to the machine frame. Clamping plate 20 also incorporates deflectors 23 to protect the nuts 22 and the ends of the bolts 15 from abrasion.

The feed section of this screening deck may be used to screen any mineral but is particularly useful for wet and dry screening of coal.

From the above it can be seen that this invention provides a unique means to address the problem of abrasion and wear of modular panels in the feed in section of a screening deck.

Those skilled in the art will realise that this invention may be implemented in embodiments other than those described without departing from the core teachings of this invention.