concept EIA-rapport - Staatsolie

SRK Consulting: Project No: 439414 Staatsolie Pipeline EIA – Draft EIA Report Page 64
Any potential impacts of the project on climate change or vice versa are considered insignificant, as:
• The pipeline is located mostly underneath the Suriname River, and rises in its level will therefore
not affect the pipeline;
• Drill pads on the riverbank are only used during the construction period; and
• The conveying of the product in the pipelines will not result in the release of significant amounts
of greenhouse gases.
6.3 Potential impact: Surface water pollution due to construction
activities
Potential impacts of routine activities during the pipeline construction phase on surface water quality
may result from:
• Disposal of surplus drilling mud into the Suriname River (see Section 6.7.1 for potential impacts
of accidental releases of drilling mud); and
• Runoff of sediments or contaminated water from construction activities.
Disposal of remaining drilling mud into the Suriname River
Some 360 tons of water based drilling mud, equating to 18 tons of bentonite, will remain in the mud
pits at the end of drilling and need to be disposed of. One option for disposal is the release of this
surplus mud into the Suriname River 32 . It is assumed that each of the four drill sections will generate
a fraction of the overall surplus mud, so that a smaller quantity of drilling mud needs to be
discharged every time a HDD section has been completed.
Bentonite is non-toxic, and based on the preliminary list of likely and possible ingredients of the
drilling mud, it is not expected that the mud will contain trace metals, which can have toxic effects on
aquatic organisms (Visser & Smit Hanab, 2011). Bentonite mud is listed on the PLONOR 33 list.
However, it could result in increased silt content in the vicinity of the release point and benthic
invertebrates, aquatic plants and fish and their eggs can be smothered by the fine bentonite particles
(Sacramento Municipal Utility District, 2001).
In a separate, unrelated study of marine, dispersion modelling for the discharge of 500 tons of drilling
mud and 500 tons of drill cuttings into the marine environment approximately 5 m above the sea bed
indicated a radial pattern of deposition. The modelled thickness of bottom deposition is highest at the
discharge source and does not exceed 10 mm at a distance of 50 m from the source. A conservative
estimate of the depth of instantaneous smothering that the major organism classes within the
benthos communities inhabiting sediments on the continental shelf would be able to survive is 5 cm
(based on research on the effects of dredged sediment on marine benthic polychaetes, molluscs and
crustaceans by Maurer et al. (1980, 1981 & 1982, cited in SRK, 2011a)). Marine benthic macrofauna
32 The other disposal option considered for the surplus drilling mud is working it into the soil of nearby farmland. Bentonite has
been successfully used in farming as an additive to degraded, light–textured soils to enrich them with nutrients, increase their
capacity to retain water and decrease erosion (e.g. in northern Thailand). The availability of sufficient farm land near the study
area and suitability of soils (many of which are already high in clay content and water logged) for enrichment with bentonite
must be determined by Staatsolie if this option is to be pursued. Due to the benign nature of bentonite and the assumed
absence of trace metals from the drilling mud, no significant negative environmental impacts are anticipated from working the
surplus drilling mud into farmland.
33 Lists substances / preparations used and discharged offshore which are considered to pose little or no risk to the
environment
REUT/DALC 439414_StaatsoliePipelineEIA_Draft EIA Report_Final June 2012