Upload
truongdiep
View
219
Download
0
Embed Size (px)
Citation preview
Incorporating Best Practice in Cyanide Code Design and Operation at the New Gold Fields
Mega TSF at South Deep.Andrè
Smuts
September 2012
Contents
1.Location and background
2.Doornpoort
Tailings Storage Facility
3.Deposition method
4.Cyanide code considerations
5.Sampling and monitoring
6.Questions
22
55
Background
Gold Fields South Africa became signatories to the International Cyanide Management (ICMI) code in 2005
The South Deep operation had its first introduction to the code GAP audit in February 2007
South Deep achieved full accreditation December 2008
18 Month Health Check: August 2010
Recertification Audit: October 2011
Recertified: February 2012
Plans to build a new TSF was finalized in 2005
Construction started in 2009
The phase one of the TSF covers some 283 hectares and was commissioned in April 2011 and the old TSF’s were
decommissioned and put on a care and maintenance program.
The phase two which will increase the size of the TSF with a further 120 hectares is to commence in 2016
77
TSF construction
16 April 2011 ‐
First days deposit on Doornpoort
1313
Started with covering the toe drains with course cyclone
underflow material
ICMI Code –
Principle 4
Most of the design was base on the requirements from Principle 4 of the International Cyanide Management
Institute Code documents
1717
Tailings delivery and return water pipeline
1818
The water and slurry pipelines are routed together in unlined earth bunding
Road way next to pipe line to allow easy access for daily inspection and maintenance
The steel pipelines is supported on concrete plinths, has anchor plinths and expansion loop
Lining
2323
The pipelines have been specified as 350NB mild steel pipelines with a 8mm HDPE inner lining.
250 mm pressure release valve.
The toe drains are offset from the inside toe line of the
starter wall
The main drain which runs parallel to the starter wall,
180 m from the outer toe line along the sides of the dam, towards the centre of the dam
Cut off drain, which runs within the starter wall, below
the crest
All three of the drains have separate outlet pipes in to
the manholes
2525
The under‐drainage system is based on three sets of drains:
Under‐drainage system
The outlet pipes from the under‐drains discharge into a sewer type system instead of the
conventional solution trench
The manholes which form part of the under drainage collection system are closed off with
grates (instead of solid lids) to prevent the build‐up of HCN within the manholes
2626
Under‐drainage system
Under‐drainage system (continue)
2929
The under drainage collection system can be directed through the neutralisation plant into the Silt trap
A cut‐off channel around the tailings dam that directs external surface run off away from the tailings and
water dams, and to contain possible spillages caused by pipe bursts
A storm water canal around the perimeter of the starter embankment which accepts the decanted water from the catchment paddocks
Return dams
3131
Capacity 1.06 million kilo liters
Lined with 2mm HDPE
Ground water pumping and leak detection monitoring.
Daily checks on Ph and WAD sampling
Sampling and monitoring
3434
Daily pipe line checks
Flow differential checks
First aid kits on the retaining walls
Mock drills for cyanide and snake bites.
Continues training of personnel.
Cell phone communication.