Introduction

Today, power gears are still widely spread in large parts of North Africa, Asia and Latin America. For most parts of the rural population they are the only practicable alternative to manual labour for works such as water raising, sugar cane crushing, and grinding of cereals and oil producing fruits. In Europe, power gears were used until the first half of this century.

The GTZ project "Documentation, Improvement and Dissemination of Animal-Powered Technology", which was begun in 1984, was based on the consideration, that power gears can facilitate work for the rural population even beyond their traditional dispersal area, provided that the use of draft animals is already known.

So far, the project has concentrated on disseminating animal-powered cereal mills in West Africa. The present guideline is based on the experience made in Senegal, Burkina Faso, Sierra Leone, Cameroon and the Central African Republic. Furthermore, individual pilot and demonstration power gears for water raising, rice husking and manioc grinding were tested in these countries.

In many African regions dishes made of flour are the main food component. Normally, the women are responsible for flour production. They grind the cereals in traditional, labour- extensive processes using wooden mortars or grinding stones.

Investigations conducted in West Africa have shown that motor mills can only work economically when they have a customer range of 1000 to 1500 consumers. Furthermore, motor mills pose quite a number of maintenance and repair problems as well as bottlenecks in fuel supply, so that often they are no practicable alternative to manual work in particular for the population in very poor, remote regions.

The animal-powered mill developed by Project-Consult on behalf of GATE, however, can be operated economically even in small villages. All maintenance and repair works can be performed by the users themselves or by local craftsmen. Nevertheless, it facilitates work very much in comparison with manual labour.

This guideline is designed to provide help for the implementation of animal-powered mills in developing countries. In Part I, the technical foundations and socioeconomic frame conditions are explained. Part II deals with the construction of animal-powered mills. The work conducted by the project so far has shown that initial difficulties of the introduction of the mill were rarely due to clearly classifiable problems, but to a complicated network of technical, cultural, economic and organisatorial problems.

The use of animal-powered mills affects several fields of problems, influences them and is influenced by them:

- Animal-powered mills are designed to facilitate the women's work, women shall use the mill and organise its operation. This is often contradictory to the roles traditionally played by men and women.
- The power of draft animals is used for driving the power gear of the mill. However, this power can only be roughly estimated and depends very much on feeding, health conditions, care and training. Often particularly the women are denied the use of draft animals.
- Animal-powered mills serve for the production of basic food. This food has to meet certain requirements, which differ very much regionally and individually. This fact calls for constructional adaptations of the mills and alterations of the traditional process of food preparation.
- The device is to be manufactured by local craftsmen, whose qualifications may vary considerably from one location to the other. The construction must always be adapted to the abilities and equipment of the craftsmen.

Every first introduction of animal-powered mills must be preceded by a thorough analysis of these framework conditions. Such an analysis is the basis for discussing all possible ways of organising the use of the animal-powered mill with the women; for planning the training of users and craftsmen; for adapting the mill to the actual local requirements; for recognizing the cause of any problems which may arise.

In most of the locations in question the thought of driving mills by draft animals is an entirely new idea. This means that every demonstration unit is judged much more critically and skeptically than a familiar technology, e.g. a motor mill. Therefore, even slight faults can result in a fundamental disapproval of the power gear technology on the part of the village population.

Hence every implementation in a village should be preceded by a trial and demonstration phase, in the course of which the technical problems can be solved and the acceptance of the flour can be tested.