SPECIAL PUBLICATION NO. 27


moving and excavating equipment. The machinery used includes drag-
lines, backhoes, grade-alls, front-end loaders and hydraulic excavators.
The majority of companies use a dragline for mining. A shredder is used
to pulverize the peat.
 Most companies drain the immediate area of mining by ditching and
pumping which enables the deposit to be mined by dry processes.
Approximately one-third of the companies contacted conduct all or part
of their mining below the watertable.
 Two companies utilize a variety of the milled peat mining process.
After surface clearing and ditching is complete, the surface peat is pul-
verized with a rotovater. The pulverized material is dried in the sun and is
turned by discing to help promote drying. The dried material is mechani-
cally windrowed using a front-end loader or bulldozer and is then stock-
piled or loaded for transport. There are no companies currently mining
peat by the sod peat method in Florida.

 INDUSTRIAL USES OF PEAT

 by
 Kenneth M. Campbell

 Industrial use of peat can be divided into two major categories: extrac-
tive and non-extractive (Minnesota DNR, 1981). The extractive uses
include direct combustion, gasification, industrial chemicals, horticul-
tural products and sewage treatment. The non-extractive uses include
agriculture, energy crops and sewage treatment (Minnesota DNR,
1981).

 Preparation of Peat for Industrial Utilization

 For most applications, peat must be dewatered before processing.
Uses for biogasification, some energy crops and sewage treatment proc-
esses do not require dewatering.
 Solar drying in the field is energy efficient but is not suitable to wet
mining processes or to all mining plans. Its feasibility is strongly depen-
dent on climate, especially rainfall. Alternative dewatering processes
include mechanical presses and thermal dryers, in addition to pretreat-
ment processes such as wet carbonization, wet oxidation and solvent
extraction.
 Mechanical methods are limited in the amount of water they can
remove. Most of the water contained in peat is held in chemical bonds,
colloidal suspensions and small pores in the organic matter. Mechanical
methods may reduce water content to 70 percent at best (Minnesota
DNR, 1981). Thermal dryers can be utilized to reduce the moisture con-
tent further. The efficiency of mechanical dewatering is greatly
enhanced by pretreatment processes such as wet carbonization, wet
oxidation and solvent extraction. Peat can be mechanically dewatered to