The solution available for minimizing the impact of quarry operations is to draw up and implement a Landscape Rehabilitation Plan.
The first landscape rehabilitation study for the Secil Outão quarries was drawn up in 1965 and the following were submitted to the authorities in 1973:
- Quarrying Plan
- Geological and Chemical Plan
- Landscape Rehabilitation Plan
These were approved in 1981 by the Setúbal Municipal Council and the authorities responsible for the Arrábida Natural Park, created in 1976.
More than 600 thousand specimens have been planted since 1982 (in quarries in operation, and abandoned quarries), over a total rehabilitation area of 70 hectares. The following figures illustrate the work carried out at the Secil Outão quarries in 2002:
- Planting: 4684 units
- Sowing of perennial herbaceous plants: 1980 m2
- Preparation of new road connecting Vale de Mós quarries A and B: 4800 m2
- Thinning of Pinus Halepenesis on platforms 330 and 334 under the protocol agreement with the Faculty of Science, Universidade Nova de Lisboa
- New irrigation system on platforms 200 and 220 in the Limestone Quarry
- Hydroseeding on Bank 200/220: 12450 m2
- New irrigation system on platforms 220/200 and 200/180 at the Marga Quarry
- Area rehabilitated: 41,310 m2
- Irrigation and maintenance: 263,950 m2
- Area monitored: 168,000 m2
Hydroseeding is a technique which consists of spraying a viscous mixture of seeds, water, fertilizers and natural fibres. These fibres may be wood or straw, and their function is to protect the seeds until germination.
This technique had been used in the past with relatively little success: a lot of the seeds failed to stay in place due to the soil characteristics, and were either washed away by the rain, or blown away by the wind.
A new hydroseeding system has been designed in collaboration with the University of Évora, in which a non-toxic, biodegradable and highly resistant fixative is added to the mixture, allowing the seeds to stick to rock; the wood fibres in the mixture provide protective cover. This offers temporary control of erosion and better humidity and temperature conditions until the vegetation takes hold.
The Landscape Rehabilitation Plan for the Maceira-Liz Quarries was approved in 1994 and is currently being implemented. The work conducted in 2002 consisted of:
- Adjudication of the detailed planning work for landscape rehabilitation to Aliança Florestal
- Planting: 1480 units
- Maintenance of planted areas
- Earthworks: 650t
- Earth placement: 17,752 t
- Final modelling of definitive embankments in zones E and F of the Limestone Quarry
- Preparation of planting areas next to the EN 356-1, with ridging
- Preparation of definitive embankments at the Limestone Quarry, with work starting on the drainage network
With regard to the Cibra-Pataias Quarries, an application was made to the Instituto Geológico e Mineiro in 2000 for the creation of a Reserve Area, and this was approved in 2002, as per the notice published in the Diário da República.
The following work was carried out in 2002 at the Cibra-Pataias quarries:
- Earthworks: 23,310 t
- Planting: 650 units
- Earth placement (embankment for the road between the crushing plant and the marl shed): 40,140 t
- Tenders invited for landscape rehabilitation designs for the area around the plant