1.2 Detalles de contacto de las personas de referencia e instituciones involucradas en la evaluación y la documentación de la Tecnología

Nombre de la(s) institución(es) que facilitaron la documentación/ evaluación de la Tecnología (si fuera relevante)

University of Stellenbosch (University of Stellenbosch) - Sudáfrica

1.3 Condiciones referidas al uso de datos documentados mediante WOCAT

¿Cuándo se compilaron los datos (en el campo)?

06/12/2001

El compilador y la/s persona(s) de referencia claves aceptan las condiciones acerca del uso de los datos documentados mediante WOCAT:

Sí

2.1 Breve descripción de la Tecnología

Definición de la Tecnología:

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

2.2 Descripción detallada de la Tecnología

Descripción:

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 Fotografías de la Tecnología

2.5 País/ región/ lugares donde la Tecnología fue aplicada y que se hallan comprendidos por esta evaluación

2.6 Fecha de la implementación

Si no se conoce el año preciso, indique la fecha aproximada:

• hace menos de 10 años (recientemente)

2.7 Introducción de la Tecnología

Especifique cómo se introdujo la Tecnología:

• durante experimentos/ investigación

Comentarios (tipo de proyecto, etc.):

Developed at University of Stellenbosch

3.2 Tipo(s) actuales de uso de la tierra donde se aplica la Tecnología

Comentarios:

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

3.3 Información adicional sobre el uso de tierras

Provisión de agua para la tierra donde se aplica la Tecnología:

• de secano

Número de temporadas de cultivo por año:

• 1

Especifique:

Longest growing period in days: 120Longest growing period from month to month: Jun - Aug

3.5 Difusión de la Tecnología

Especifique la difusión de la Tecnología:

• distribuida parejamente sobre un área

Si la tecnología se halla difundida homogéneamente en un área, indique el área aproximada que cubre:

• 1-10 km2

3.6 Medidas MST que componen la Tecnología

Comentarios:

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 Principales tipos de degradación del suelo encarados con la Tecnología

Comentarios:

Main causes of degradation: industrial activities and mining

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

3.8 Prevención, reducción o restauración de la degradación del suelo

Especifique la meta de la Tecnología con relación a la degradación de la tierra:

• restaurar/ rehabilitar tierra severamente degradada

4.1 Dibujo técnico de la Tecnología

4.2 Especificaciones técnicas/ explicaciones del dibujo técnico

Technical knowledge required for field staff / advisors: moderate

Technical knowledge required for land users: moderate

Main technical functions: reduction in wind speed

Secondary technical functions: improvement of ground cover, increase in organic matter, increase of infiltration, increase in soil fertility

Scattered / dispersed
Vegetative material: O : other
Number of plants per (ha): 2000
Vertical interval within rows / strips / blocks (m): 5

Other species: Succulent plants

Slope (which determines the spacing indicated above): 4.00%

Structural measure: silt fence
Spacing between structures (m): 5
Height of bunds/banks/others (m): 0.8

Construction material (other): nylon net - small grid size

Silt fence: all 5m and height of 0.8m

4.3 Información general sobre el cálculo de insumos y costos

otra / moneda nacional (especifique):

Rand

Indique la tasa de cambio de USD a la moneda local (si fuese relevante): 1 USD =:

9,07

4.4 Actividades de establecimiento

	Actividad	Tipo de medida	Momento
1.	Collection of plants from natural vegetation	Vegetativas	Pre-rainy season
2.	Collection of plants from topsoil stockpiles	Vegetativas	Pre-rainy season
3.	Transport plants to rehabilitation area	Vegetativas	Pre-rainy season
4.	Plant all plants	Vegetativas	Pre-rainy season
5.	Insert droppers into net pockets	Estructurales	all year
6.	Spread nets over topsoil areas	Estructurales	all year
7.	Erect nets and hammer in droppers	Estructurales	all year

4.5 Costos e insumos necesarios para el establecimiento

	Especifique insumo	Unidad	Cantidad	Costos por unidad	Costos totales por insumo	% de los costos cubiertos por los usuarios de las tierras
Mano de obra		hectare	3,0	75,0	225,0	100,0
Equipo	machine	hectare		67,0		100,0
Material para plantas	seedling	hectare				100,0
Material de construcción	nylon netting	hectare		70,0		100,0
Costos totales para establecer la Tecnología					225,0

4.6 Actividades de establecimiento/ recurrentes

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

4.7 Costos e insumos necesarios para actividades de mantenimiento/ recurrentes (por año)

	Especifique insumo	Unidad	Cantidad	Costos por unidad	Costos totales por insumo	% de los costos cubiertos por los usuarios de las tierras
Mano de obra	labour	hectare	37,0

Comentarios:

Per hectare

4.8 Factores más determinantes que afectan los costos:

Describa los factores más determinantes que afectan los costos:

Labour costs

5.1 Clima

5.2 Topografía

5.3 Suelos

Si se halla disponible, adjunte una descripción completa de los suelos o especifique la información disponible, por ej., tipo de suelo, pH/ acidez de suelo, capacidad de intercambio catiónico, nitrógeno, salinidad, etc. :

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

5.6 Las características de los usuarios de la tierra que aplican la Tecnología

Indique otras características relevantes de los usuarios de las tierras:

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 Área promedio de la tierra que pertenece a o es arrendada por usuarios de tierra que aplican la Tecnología

5.8 Tenencia de tierra, uso de tierra y derechos de uso de agua

Tenencia de tierra:

• estado
• individual, con título

Derechos de uso de tierra:

• arrendamiento

6.1 Impactos in situ demostrados por la Tecnología

Impactos socioeconómicos

Producción

Impactos socioculturales

Impactos ecológicos

Suelo

Biodiversidad: vegetación, animales

Reducción de riesgos de desastres y riesgos climáticos

6.2 Impactos fuera del sitio demostrados por la Tecnología

6.4 Análisis costo-beneficio

¿Cómo se comparan los beneficios con los costos de establecimiento (desde la perspectiva de los usuarios de tierra)?

¿Cómo se comparan los beneficios con los costos de mantenimiento/ recurrentes (desde la perspectiva de los usuarios de tierra)?

6.7 Fuerzas/ ventajas/ oportunidades de la Tecnología

Fuerzas/ ventajas/ oportunidades desde la perspectiva del compilador o de otra persona de referencia clave
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 Debilidades/ desventajas/ riesgos de la Tecnología y formas de sobreponerse a ellos

Debilidades/ desventajas/ riesgos desde la perspectiva del compilador o de otra persona de referencia clave	¿Cómo sobreponerse a ellas?
Rehabilitation is an extra cost for the mining company.	Ensure mining company meets the costs through enforcing legislation.