NAMAGROEN EMPR Amendment.pdf - DLIST Benguela

Addendum to EMPR for Concessions 8(a), 9(a) and 8(b) 27Miningexcavations:Hydrographical changesDredging excavations and trenchesmay affect patterns in the waveregime on a regional scale, whichmay in turn affect nearshoresediment transport. This mayultimately result in correspondingchanges to beach morphodynamics.StatusNegativeProbability Unknown but improbable; any changes inwave patterns are likely to have dissipatedby the time they reach the coastline.Confidence MediumExtent Local to Regional; changes in the shorelinemay occur opposite and to the north ofpersistent trenches.Duration Long-term to Permanent; changes inhydrographical conditions andcorresponding shoreline changes maypersist over the long term, or may even bepermanent.Intensity Negligible; changes in beachmorphodynamics on the exposed coastlineas a result of shoreline changes areunlikely to severely change thecommunities associated with this habitat.Significance LowOverspill during dredging:Suspended sediment plumesVisible sediment plumes caused byfine particles suspended near thewater surface causing both a visualimpact, decrease in lightpenetration thereby affectingprimary production and lethal orsublethal effects on marineorganismsStatusNegativeProbability Improbable; although elevated suspendedsediment concentrations are a typical byproductof mining activities, effects onmarine organisms are unlikely.Confidence HighExtent Local; the extent and area over whichplumes disperse will depend on thestrength and direction of the prevailingcurrents and winds, and the particle size ofthe material in question.Duration Short-term; plumes will be rapidlydispersed and advected away from thevessel, however, potential effects willextend over the duration of the dredgingactivity in the concession area (Mediumterm).Intensity Mild; adverse effects are experiencedgenerally at suspended sedimentconcentrations higher (>100 mg/l) thanthose expected during dredging operations,or to longer exposure periods (>2 days)than typical life times of suspendedsediment plumes.Significance LowNamagroen Prospecting & Investments October 2008