1.2 Coordonnées des personnes-ressources et des institutions impliquées dans l'évaluation et la documentation de la Technologie

Nom du projet qui a facilité la documentation/ l'évaluation de la Technologie (si pertinent)

Book project: where the land is greener - Case Studies and Analysis of Soil and Water Conservation Initiatives Worldwide (where the land is greener)

Nom du ou des institutions qui ont facilité la documentation/ l'évaluation de la Technologie (si pertinent)

University of Stellenbosch (University of Stellenbosch) - Afrique du Sud

1.3 Conditions relatives à l'utilisation par WOCAT des données documentées

Le compilateur et la(les) personne(s) ressource(s) acceptent les conditions relatives à l'utilisation par WOCAT des données documentées:

Oui

2.1 Courte description de la Technologie

Définition de la Technologie:

Rehabilitation of areas degraded by strip mining, through returning stockpiled topsoil and transplanting of indigenous species, to promote revegetation.

2.2 Description détaillée de la Technologie

Description:

In contrast to the land degradation commonly caused when ‘strip mining’ is carried out, a land rehabilitation technology, which was first developed experimentally, is now routinely applied by mining companies on the west coast of South Africa. Indeed it is now a legal requirement in South Africa for mining companies to rehabilitate mined areas to a condition and productivity equivalent to the pre-mining situation.
The primary purpose of the technology described here is to achieve this result – thus allowing the site to be used again for extensive grazing by sheep and wild animals. Revegetation also reduces wind erosion. The technology further contributes to increasing biodiversity, as particular attention is given to planting a range of locally endemic and other indigenous species.
The sequence of operations is as follows: during strip mining operations the topsoil is pushed to one side by bulldozer, and stockpiled. The substrata is then excavated mechanically, removed by tipper truck, and processed to extract the heavy metals. The tailings (waste materials) are returned by tipper truck to the area from which they were mined, and then levelled by bulldozer. The stockpiled topsoil is returned and spread by bulldozer over the levelled tailings. Indigenous succulents and other plant species are dug out by hand, with a spade, from either the surrounding areas of natural vegetation, or from the piles of topsoil (where plants may have naturally established) and transplanted manually into the newly spread topsoil. The planted areas are protected from wind erosion by erecting fine mesh nylon netting as windbreaks. These are 0.8 metre high and 5 metres apart. The nets are usually installed for a period of up to 2-3 years. Subsequently they are removed, once the vegetation has successfully become re-established, and they may be re-used at the next rehabilitation site. Maintenance activities continue for a few years – until the site is rehabilitated. An individual mine strip is usually about 1 km long and some 100 m wide.
This form of strip mine rehabilitation has been in operation since 1990, and costs on average just over US$ 200 per hectare, with all expenses met by the mining company. This particular approach was developed for the Anglo-American subsidiary – ‘Namaqua Sands’. A similar approach was adopted by ‘PBGypsum Mines’ located further inland, where rehabilitation is also conducted on several hundreds hectares of mined land. Not all mining companies use the same technology, however.

Purpose of the Technology: Establishment activities:
Mining activities (not part of technology)
1.Removal and stock piling of topsoil
2.Excavation, removal and processing of substrata to extract heavy minerals
3.Return and levelling of the mine tailings
4.Return and spreading of topsoil Technology activities
5.Collection/digging up of indigenous plants
6.Transplanting into returned topsoil
7.Erection of fine mesh nylon net windbreaks Activities 1-4 are a continuous process associated with the speed of mining activities and involve the use of heavy earth moving machinery (bulldozers, front end loaders, tipper trucks). Activities 5&6 take place immediately prior to the onset of the rainy season and involve hand labour for collection and transplanting and tractor and trailer for transporting collected plants. Activity 7 can take place at any time of the year involving hand labour for erection of the nets and tractor and trailer for transport.

Maintenance / recurrent activities per year:
Maintenance activities restricted to:
1.Ensuring the nylon nets remain upright
2.Supplementary watering during the winter months, when rainfall inadequate, to support plant growth

2.3 Photos de la Technologie

2.5 Pays/ région/ lieux où la Technologie a été appliquée et qui sont couverts par cette évaluation

2.6 Date de mise en œuvre de la Technologie

Si l'année précise est inconnue, indiquez la date approximative: :

• il y a moins de 10 ans (récemment)

2.7 Introduction de la Technologie

Spécifiez comment la Technologie a été introduite: :

• au cours d'expérimentations / de recherches

Commentaires (type de projet, etc.) :

Developed at University of Stellenbosch

3.2 Type(s) actuel(s) d'utilisation des terres, là où la Technologie est appliquée

Commentaires:

Major land use problems (compiler’s opinion): Overgrazing

Major land use problems (land users’ perception): Aridness and climate change. Erratic rainfall/climate. Frequent drought.

Ranching: Yes

Constraints of mines and extractive industries: Stockpiling of topsoil; processing of subsoil

Number of growing seasons per year: 1
Longest growing period in days: 120Longest growing period from month to month: Jun - Aug

3.4 Approvisionnement en eau

Approvisionnement en eau des terres sur lesquelles est appliquée la Technologie:

• pluvial

3.6 Mesures de GDT constituant la Technologie

Commentaires:

Specification of other vegetative measures: translocation of indigenous plants

Specification of other structural measures: land levelling, artificial windbreaks

Type of agronomic measures: zero tillage / no-till

Type of vegetative measures: scattered / dispersed

3.7 Principaux types de dégradation des terres traités par la Technologie

Commentaires:

Main causes of degradation: industrial activities and mining

Secondary causes of degradation: over-exploitation of vegetation for domestic use, overgrazing

3.8 Prévention, réduction de la dégradation ou réhabilitation des terres dégradées

Spécifiez l'objectif de la Technologie au regard de la dégradation des terres:

• restaurer/ réhabiliter des terres sévèrement dégradées

4.1 Dessin technique de la Technologie

4.2 Informations générales sur le calcul des intrants et des coûts

autre/ monnaie nationale (précisez):

Rand

Indiquez le taux de change des USD en devise locale, le cas échéant (p.ex. 1 USD = 79.9 réal brésilien): 1 USD = :

9,07

4.3 Activités de mise en place/ d'établissement

	Activité	Calendrier des activités (saisonnier)
1.	Collection of plants from natural vegetation	Pre-rainy season
2.	Collection of plants from topsoil stockpiles	Pre-rainy season
3.	Transport plants to rehabilitation area	Pre-rainy season
4.	Plant all plants	Pre-rainy season
5.	Insert droppers into net pockets	all year
6.	Spread nets over topsoil areas	all year
7.	Erect nets and hammer in droppers	all year

4.4 Coûts et intrants nécessaires à la mise en place

	Spécifiez les intrants	Unité	Quantité	Coûts par unité	Coût total par intrant	% des coût supporté par les exploitants des terres
Main d'œuvre	Labour	hectare	1,0	75,0	75,0	100,0
Equipements	Machine use	machine hours	0,5	134,0	67,0	100,0
Matériel végétal	Seedlings	ha	1,0			100,0
Matériaux de construction	Nylon net	ha	1,0	70,0	70,0	100,0
Coût total de mise en place de la Technologie					212,0
Coût total de mise en place de la Technologie en dollars américains (USD)					23,37

4.5 Activités d'entretien/ récurrentes

	Activité	Calendrier/ fréquence
1.	Topsoil pushed into stockpile	all seasons / continuous
2.	Subsoil removed and processed	all seasons / continuous
3.	Processed subsoil returned to mined area and levelled	all seasons / continuous
4.	Stockpiled topsoil spread over processed subsoil	all seasons / continuous
5.	Plants transplanted onto spread topsoil	just before rainy season / late autumn/winter
6.	Ensure nets remain upright	all year/continuous

4.6 Coûts et intrants nécessaires aux activités d'entretien/ récurrentes (par an)

	Spécifiez les intrants	Unité	Quantité	Coûts par unité	Coût total par intrant	% des coût supporté par les exploitants des terres
Main d'œuvre	Labour	ha	1,0	37,0	37,0
Coût total d'entretien de la Technologie					37,0
Coût total d'entretien de la Technologie en dollars américains (USD)					4,08

Commentaires:

Per hectare

4.7 Facteurs les plus importants affectant les coûts

Décrivez les facteurs les plus importants affectant les coûts :

Labour costs

5.1 Climat

5.2 Topographie

5.3 Sols

Si disponible, joignez une description complète du sol ou précisez les informations disponibles, par ex., type de sol, pH/ acidité du sol, capacité d'échange cationique, azote, salinité, etc.

soil fertility: very low, soil drainage / infiltration = low, soil water storage capacity = low

5.6 Caractéristiques des exploitants des terres appliquant la Technologie

Indiquez toute autre caractéristique pertinente des exploitants des terres:

Population density: < 10 persons/km2

Annual population growth: < 0.5%

80% of the land users are average wealthy.
20% of the land users are poor.

Off-farm income specification: Most of income from mining

5.7 Superficie moyenne des terres utilisées par les exploitants des terres appliquant la Technologie

5.8 Propriété foncière, droits d’utilisation des terres et de l'eau

Propriété foncière:

• état
• individu, avec titre de propriété

Droits d’utilisation des terres:

• loué

6.1 Impacts sur site que la Technologie a montrés

Impacts socio-économiques

Production

Impacts socioculturels

Impacts écologiques

Sols

Biodiversité: végétale, animale

Réduction des risques de catastrophe et des risques climatiques

6.2 Impacts hors site que la Technologie a montrés

6.4 Analyse coûts-bénéfices

Quels sont les bénéfices comparativement aux coûts de mise en place (du point de vue des exploitants des terres)?

Quels sont les bénéfices comparativement aux coûts d'entretien récurrents (du point de vue des exploitants des terres)?

6.7 Points forts/ avantages/ possibilités de la Technologie

Points forts/ avantages/ possibilités du point de vue du compilateur ou d'une autre personne ressource clé
Low establishment costs and very low maintenance costs How can they be sustained / enhanced? Make use of whatever resources and potentials are naturally available (such as micro-catchments to trap rainwater and improve soil moisture conditions for plants) to lower establishment costs.
Costs are met by the mining company – no costs are transferred to those who subsequently use the land for grazing How can they be sustained / enhanced? Regular monitoring of soil and vegetation conditions.
Land productivity is restored and biodiversity increased How can they be sustained / enhanced? Seeding as well as transplanting.
Wind erosion minimized.

6.8 Faiblesses/ inconvénients/ risques de la Technologie et moyens de les surmonter

Faiblesses/ inconvénients/ risques du point de vue du compilateur ou d'une autre personne ressource clé	Comment peuvent-ils être surmontés?
Rehabilitation is an extra cost for the mining company.	Ensure mining company meets the costs through enforcing legislation.

7.1 Méthodes/ sources d'information