BS EN 16907-7 pdf free download

BS EN 16907-7-2021 pdf free download.Earthworks – Part 7: Hydraulic placement of extractive waste.
The effective storage of the hydraulic fill, and the efficient recycling of the resulting water, requires the appropriate design, operation and management of the mineral processing and extractive waste storage system to achieve long-term (in perpetuity) safe and sustainable storage and geotechnical and geochemical stability. The options for transport from the mineral processing plant and for placement and deposition in a stable MWF are numerous, but the principal drivers are the long-term goal of safe, stable and efficient storage referred to above.
The MWF may vary in area from less than 10 000 m2 to several square kilometres and in height from a few metres for an aggregate silt lagoon to over 100 m for a tailings management facility for a large and complex, e.g. polymetallic, mining operation. Typical sections through a tailings management facility and a silt lagoon are shown in Figures 1 and 2 and provide an indication of the key features of such MWFs. It is noted that, depending on the setting, not all of the features shown may be required.
The fine-grained extractive waste resulting from mineral processing is usually pumped or fed under gravity in slurry form from the mineral processing plant to the MWF. The consistency of the slurry will vary from project to project dependent on the geological origin of the ore, its geotechnical characteristics, the industrial processing, the configuration of the storage basin and the geographical setting. The slurry may take the form of a thin pulp with solids concentrations as low as 5 %, as for many silt lagoons, or be thickened to 70 % or 80 % solids and be deposited as a paste or thickened tailings hydraulic fill.
6 Mine Waste Facility Characterization
Under current European legislation (Directive 2006/21/EC), the Competent Authority classifies a MWF under Category A if:
1 failure or incorrect operation, e.g. the collapse of a heap or the bursting of a dam, could give rise to a major accident, on the basis of a risk assessment taking into account factors such as the present or future size, the location and the environmental impact of the waste facility; or
2 it contains waste classified as hazardous under Directive 91/689/EEC above a certain threshold; or
3 it contains substances or preparations classified as dangerous under Directives 67/548/EEC or
1999/45/EC above a certain threshold. 2006L0021 —EN —07.08.2009 — 001.00 1— 28
A MWF is classified as non-Category A if none of the above criteria are met.
The characterization of the extractive waste shall consider the parameters referred in 2 and 3, above.
7 Site and material characterization
7.1 General
Geotechnical and geochemical characterization of foundation materials, construction materials and extractive waste shall be carried out for all mine waste facilities. This Clause describes geotechnical and geochemical characterization, with an emphasis on the former, as geochemical characterization is covered in detail in other standards.
A geotechnical investigation shall be carried out for all new mine waste facilities, and prior to the expansion and modification of existing mine waste facilities. The geotechnical investigation shall collect, record, and interpret geotechnical information, including geology, geomorphology, seismicity, hydrology and history of the site.
The scope of the geotechnical investigation shall be such that adequate and sufficient information on ground conditions and availability of construction materials is obtained for design and construction. The scope shall take into account the nature and classification of the mine waste facility.
Geotechnical investigations shall meet the requirements outlined in EN 1997 (series) and EN 16907 (series).
NOTE 1 Mine waste facilities classified under Category A in accordance with Directive 2006/21/EC can be classified as Geotechnical Category 3, in accordance with EN 1997- 1, when defining minimum requiremenLs for the extent and content of a geotechnical investigation. Mine waste facilities not classified under Category A can also be classified as Geotechnical Category 3 unless there is sufficient evidence to indicate that the structure does not pose exceptional risk and there are no difficult ground or loading conditions.
Given the unacceptable risk of undermining the mine waste facility, the selected site should be investigated by condemnation drilling or by other means in order to assess the presence of a deposit of economic merit.
The extractive waste to be deposited in a mine waste facility shall be characterized in such a way as to allow the long-term physical and chemical stability of the structure to be assessed. Waste characterization shall cover all the following categories of information:
— background information;
— geological background of deposit to be exploited;
— the nature of the waste and its intended handling;
— geotechnical behaviour of waste;
— geochemical characteristics and behaviour of waste.
NOTE 2 This information is specified in Commission Decision 2009/360/EC.
The above information shall be included in a waste management plan for the mine waste facility.
In Directive 2006/21/EC, waste characterization for mine waste facilities classified under Category A shall be carried out at different stages of the project, starting at initial design and ending at closure (both active and passive). Waste characterization shall also be required whenever there is a change in the characteristics of the material deposited in a mine waste facility and the results shall be included in a revised waste management plan.
When characterizing waste, reference should be made to documents produced by CEN/TC 292, in particular EN 14899, EN 15875, CEN/TS 16229, CEN/TR 16363, CEN/TR 16365, CEN/TR 16376. Reference should also be made to available specialized literature, as indicated in the Bibliography.
7.2 Stages of the characterization process
The planning, design, construction, operation and closure of a mine waste facility shall be based on a detailed knowledge of the geotechnical and geochemical characteristics of the extractive waste to be deposited, of any construction materials used to build the confining structure, and of all foundation materials under the facility.
NOTE Although many mine waste facilities incorporate geosynthetics into their design, these materials are not considered in this document.BS EN 16907-7 pdf download.