Scraper reclaimers

Limestone may be reclaimed from stockpiles by a variety of mechanisms, including conveyers in tunnels below the stockpile, scraper reclaimers and mobile shovels. 

Good homogenizing or blending effects are also attained with the strata method and side-acting scraper reclaimers. 

Fig. 35 Stacking and reclaiming of a blending bed based on the cone shell-method overhead stacker belt, longitudinally travelling scraper reclaimer...

Drag-line scrapers employ bucketlike scoops or disks which are moved back and forth by steel cables to drag loose materials from a large storage area, usually outdoors, toward a central elevator or conveyor hopper for subsequent delivery to the plant. Such equipment is used for storing and reclaiming materials like coal or stone. 

Scraper chains are unsuitable for reclaiming from a stockpile built up in horizontal layers. Front-acting machines, as described in 3.2.1.2, must be used for the purpose. Reclaiming from piles with inclined layers may be done not only with front-acting but also with side-acting scrapers. 

Reclaiming from homogenizing troughs can be done with scrapers or with bucket-ladder (or chain-bucket) machines. 

The alternative system consists in windrow stacking with reclaiming by means of side-acting scrapers. The MIAG "step-back" method is more particularly suitable for this purpose. 

Reclaiming with side scrapers has the disadvantage that the rate of flow of the reclaimed material is not constant, while the homogenizing effect is less good than that obtained with front-acting machines. 

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