Development and Future Trends in Bunker Storage

Abstract

ABSTRACT The Grain Handling Authority of N.S.W. has developed a system of bunker-type storage that was originally envisaged as an extension of the technique of temporary storage. This has now reached the stage where it is a satisfactory form of permanent storage where only minimal capital requirements are warranted, where capital is simply not available for the construction of storages, or where a storage facility must be provided at very short notice. The PVC-covered bulk grain storage system is capable of directly responding to two of the current needs of bulk handling organizations: the need to minimise handling and storage costs, and the need to control insect infestation in grain without the use of chemical protectants and, possibly, without the use of fumigants. These storages are now routinely being constructed to 50,000 tonne capacity, and feature movable concrete banks and bitumen surface. A range of portable grain handling equipment has been designed to complete the new storage and handling system. The operational problems encountered in bunker storages include grain contamination with earth, damage to the covers and difficulties with grain receival under some conditions. All these problems have been overcome or reduced to a low level. A major advantage of the PVC bunker-type storage is that it can be fumigated satisfactorily with phosphine. This treatment is a very cheap form of fumigation and experience to date indicates that the storages are sufficiently gastight to render it completely effective. Grain storage in bunker systems is now substantially cheaper than in permanent structures (e.g. steel bins $20 per tonne capacity, bunkers ca. $8 per tonne capacity per annum, including handling and capital charges).