Dust Control Handbook for Industrial Minerals Mining and Processing

For many years, this plastic wrapping technique was the best and least expensive method ofprotecting loads for shipment [Packaging system 1978]. One shortcoming with the spiral stretchwrap is that the top of the pallet is not normally sealed and dust can be liberated from this toparea. In addition, when the pallets are outside, rain or moisture can get down in and saturate thebags of product. To correct this shortcoming, a top sheet can first be placed over the top of thepallet before the process is started, but this normally has to be performed manually by a worker,which increases the time and the cost of performing this process.Another method to perform this plastic wrapping technique is through the use of shrink wraps orstretch hoods. This technique uses a single sheet of plastic which is placed over the entire palletand then heated to cause it to shrink tightly down completely around the pallet of bags. Thistechnique can also be performed manually by a worker or through the use of an automatedsystem. When using this technique, pallets can be stacked and stored outside without worryingabout water damage during storms. Stretch-hooded pallets are safer than shrink wrap palletsbecause the pallets are more stable and easier to handle [New Installations 2006].FLEXIBLE INTERMEDIATE BULK CONTAINERSFlexible Intermediate Bulk Containers (FIBCs), also called "bulk bags," "semi-bulk bags,""mini-bulk bags," and "big bags," have become more popular over the recent years for shipmentof product material. They are often more cost-effective than the 50-, 80-, or 100-pound bags forboth the mineral producer and the end user. The most effective method to control the dustliberated during filling of FIBCs is by using an expandable neoprene rubber bladder in the fillspout of the bagging unit. This bladder expands against the interior of the FIBC loading spoutand completely seals it, eliminating any product and dust escaping from the spout during loading(Figure 6.20). When using this expansion bladder, the feed spout must also incorporate anexhaust ventilation system to exhaust the excess pressure from the FIBC during loading(Figure 6.21).Figure 6.20. Expandable neoprene rubber bladder used in the fill spoutof the bagging unit for Flexible Intermediate Bulk Containers.Bagging 181