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Managing Environmental Impacts

CASE STUDY 1

In 1992 the French Aggregates Industry developed the 'Environmental Charter for an Integrated Environmental Management Commitment by Professionals'. This is aimed at encouraging best practices in their sector.

In 2002 they broadened their commitment to sustainable development with the Charter as the environmental pillar.

For centuries, quarrying activities have played a major role in mankind's development in all forms of building, whether it is for housing, building a motorway or bridges to link different communities and people.

Today, when some human activities have an impact on the ecological balance, the aggregates producers intend to demonstrate their responsible behavior in committing themselves to better integrate quarrying activities into the environment.

In order to meet the objectives of sustainable development, the Charter National Committee has developed a specific guideline for quarrying activities as well as a follow-up system to support signatory companies in this exercise.

This system enables participating companies to set target objectives for themselves, to benefit from a pool of financial and technical resources and progressively to act in an autonomous way.

THE COMMITMENT

All signatory companies to the Charter commit themselves on a voluntary basis to improve the environmental management of their quarrying activities. They are supported by an auditing checklist.

TOOLS AND ACTORS

The auditing grid of 6 areas consists of the following: Impact Management, Integration into landscape, Dialogue, Organization, Responsibility.

There is also a four-stage approach to enable each operating site to assess its situation and achievements

• Stage 1, Assessment
  The company has assessed its environmental management practices and has appointed a key contact person. It has developed an action plan and started implementing the first measures.
• Stage 2, Action Plan
  The company has laid down the foundations for an integrated environmental management system by organizing employee training and is developing the means to better respect the environment.
• Stage 3, Improvement
  The company has broadened its skills and implemented ways to manage its main impacts on the environment. In addition, it has implemented measures to improve the dialogue with the local community in which it operates.
• Stage 4, Validation
  The company now manages properly the environmental impacts of its operations. Local and regional partners acknowledge its achievements.

The company is now autonomous and can work in optimizing good practices during its operations and for site rehabilitation with: a Charter key contact in each signatory company; an auditor adviser supporting signatory companies at regional level; a validating Committee when the fourth level is reached.

Signatory companies commit themselves in a collective project, which implements the sustainable development concept by integrating economic development, environmental conservation and dialogue with local stakeholders.

CASE STUDY 2

Pioneer Concrete Hispania, S.A. has been quarrying aggregate for construction since 1980 on the “El Gordillo” property in La Rinconada (Seville - Spain).

Respect for the environment has been a top priority since the start of the operation, and all work undertaken in both the planning and mining stages have constantly been subordinated to the need to restore the affected land. This working system is an example of modem, environmentally-sensitive mining practice in the aggregate sector, which has traditionally been severely criticised for its previous habits. The Pioneer operation has become a trend- setting point of reference for the rest of the quarry operators in the area.

MINING METHOD

The operation involves the extraction of loosely bound detritus material (of terrace on the Guadalquivir River). The material has therefore been removed by mechanical means in open cast pits.

This is in fact a largely horizontal sedimentary deposit of soft material in layers, with three mining benches- one sterile and two mineral benches, the first one of which is above the water table and the second in the saturated gravel zone.

RESTORATION

After analysing the geo-environmental and cultural factors and the absorption capacity of the area, the company selected the most appropriate agricultural use for the recovery and restoration of the property.

To date, 90 hectares have been restored. The remaining 11 hectares yet to be treated are the areas occupied by the treatment plant, stockpiles and ponds.

This area will be restored at the end of the quarry lifetime, and is planned in such a way that the continuity of the previous work will not be affected.

The restoration work has been undertaken linked to the exploitation progress apart from specific cases where this has not been technically possible.

The largest sized material was always laid at the bottom of the pit to facilitate local groundwater circulation. It is important to note that recent studies have proven that the backfill areas are permeable and that the aquifer has not been interrupted in the exploited areas although flow may be reduced,

In order to prevent water backup and swamping, the restored areas have been levelled and provided with the necessary drainage infrastructure as well as deep scarifying to improve the land filtering capacity.

The restored areas were finally turned over to the property owner in optimum conditions for farm production, with a high return on tomato, cottony and potato drops to date.

The restored land was levelled with a 2:1000 slope. While this has eliminated the erosion hazard, perimeter drainage ditches have been designed as well as zones where water is captured from surrounding fields to achieve the following objectives:

• Minimised erosion, soil loss and silting due to storm water runoff
• Controlled flooding and swamping hazards
• Removal of obstacles to agricultural work

Embankments with a slope of close to 8% have been formed to permit farm labour so as to prevent the loss of arable soil. In these cases, a guard ditch has been constructed at the head of the embankment.

IMPROVEMENTS TO THE PROPERTY

The following list describes some of the key operations undertaken on the property:

• Levelling was one of the most important improvements, as the original topography was extremely uneven, preventing continuous mechanised farm work across the property.
• The land was uniformly flattened and lowered 6 metres from its original level. This has permitted the installation of a gravity-fed drip irrigation system throughout the restored area, with the associated savings in electricity and water consumption, a fundamental improvement in this drought-afflicted region.
• Another important improvement has been the channelling and piping of storm water that previously entered the property from surrounding fields, thus preventing the free flow of water across the farmland which previously hindered tilling work on the soil.
• The electricity, water and telecommunications supply lines have been diverted to remove all obstacles to the full exploitation of the property.
• Unquestionably the largest infrastructure work undertaken during the quarry operation was the construction of a dam with a water storage capacity of 1.000.000 m3.
  This dam is fed using surplus water from the Lower Guadalquivir Valley Canal which would otherwise be lost, as well as rainwater runoff from surrounding properties which previously flowed unimpeded through the cropland and hindered agricultural work. It is now channeled and piped into the dam. By this means, the irrigation water supply to the property is guaranteed, even during the regular droughts in the area

TECHNICAL DIFFICULTIES

The company has been able to harmonise business productivity with land restoration needs and compliance with Government requirements on the basis of a large dose of effort, ingenuity and enthusiasm for doing a good job.

The most serious technical problems that have arisen during restoration work on the land affected by the quarry are described below:

• The greatest challenge tackled during the restoration of the property was the construction of a 1.000.000 m3 dam to store irrigation water.
• Another problem was the lack of refill material in certain zones due to the variations in the depth of the sterile and gravel layers. These variations are commonplace in this type of mine, and caused a shortfall in backfill material which was resolved with a stockpile of inert material brought from the excavations for the Olympic Stadium in Seville.
• Given that the area affected by the quarry (101 ha) was lowered approximately 6 m from its original level, another difficulty to resolve was drainage. This was done by two means. On the one hand, water entering from the surrounding properties on higher land was channelled into the dam, and on the other, the water affecting the property itself was drained along the levelling slopes towards the natural drainage lines in the area.
• Finally, it is important to stress that the commitment to reducing the affected area to a minimum has been a serious planning challenge for the stripping, backfill and advance operations on the quarry faces. The success of the venture has permitted the handover of restored land at the same pace as the progress of quarry operations, making farming compatible with mining.
  

introduction | codes of conduct | social audits | socially responsible investment | health & safety | managing environmental impacts | community involvement | environmental auditing | voluntary agreements | reporting