The peat produced during the summer is
storaged in the stockpiles for deliveries during the heating season. Peat reserve storages
are needed in order to insure the delivery of peat after poor production seasons. Every
production method has its own special features for storaging technology. The
successfullness of storaging depends on the successfullness of the stockpiling. The peat
can become moist in a stockpile and the surface of the stockpile can be frozen in winter
or the peat can be self-heated so that it ignits. This causes energy losses and decreases
the quality.
In Haku and Tehoturve methods the stockpiles
are made either by driving new peat above the earlier peat layer or by using a bulldozer.
At the end of a production season the stockpiles are shaped with bulldozers to steep
sloped and they are compacted throughly. Well shaped and compacted milled peat stockpiles
remain in fairly good condition without any protective measures. The volume of the
stockpiles is 30 000 - 50 000 m3.
In Finland the sod peat is usually stockpiled
using an excavator. Because of this the stockpiles are long, equally high and triangle
sheped. The height of them is usually about 5.0 meters and the volume of one meter of
stockpile is 30 - 40 m3 of sod peat. Two factors cause losses in sod peat stockpiling:
wetting and self-heating. Sod peat stockpiles are usually covered with plastic foil in
order to prevent wetting. The durability of the coverings is usually about a half year, so
if the stockpiles are to be kept longer they have to be re-covered. Additionally, the
plastic foil residues cause problems in peat production areas. The best way to prevent
selfheating of the sod peat stockpiles is the fine matter free stockpile. This can be
obtained by using strong sods of even moisture content, as well as by making the stockpile
with a stockpile sieve instead of an excavator. The sieving machine sieves the sod peat
and transports it into stockpile.
Other milled and sod peat stockpile covering
materials, such as wood chips, sawdust and straw have been tested. The results have been
promising because these stockpile coverings can be combusted with the peat.