# Commission Decision of 20 April 2009 on the definition of the criteria for the classification of waste facilities in accordance with Annex III of Directive 2006/21/EC of the European Parliament and of the Council concerning the management of waste from extractive industries (notified under document number C(2009) 2856) (2009/337/EC), Annex I: Formula for the calculation of the average yearly increase in stored water within the tailings pond ΔQ as referred in Article 8 paragraph 2

Extent: E+W+S+N.I.

ΔQi (ΔΜi/D) * P, where:
ΔQi yearly increase of stored water in the tailing pond (m3/year) during the year ‘i’
ΔΜi yearly mass of tailings discharged to pond (tonnes dry weight/year) during the year ‘i’
D average dry bulk density of the deposited tailings (tonnes/m3)
P average porosity of the sedimented tailings (m3/m3) defined as the ratio of the volume of voids to the total volume of sedimented tailings
If exact data are not available, default values of 1,4 tonnes/m3 for the dry bulk density and 0,5 m3/m3 for the porosity should be used.

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Source: https://www.legislation.gov.uk/eudn/2009/337/annex/I (the official version)
Page: https://openlegislation.uk/eu-decision-2009-337/annex-I
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.