PINEY POINT GYPSUM STACK SYSTEM SPRING 2003 January 2003 STACK SYSTEM CLOSURE Contracts Already Awarded for 3 Lined Reservoirs NGS-N OGS-N OGS-S NGS-N CLOSURE CONCEPT NORTH-SOUTH CROSS SECTION AVAILABLE STORAGE 125 MGal LINED STORAGE 270 MGal RAISED DIKES OLD GYPSUM STACK-NORTH (OGS-N) RELIEF DITCH SEEPAGE COLLECTION DITCH HDPE LINER NEW GYPSUM STACK-NORTH (NGS-N) LINED RESERVOIRS 1. Interim Use - Process Water or Fresh Water Storage 80-mil HDPE Process Water or Fresh Water 2. Long Term Use – Fresh Water Reservoir Grassed Surface (Seeded or Sodded) 80-mil HDPE Soil Cover Fresh Water February 2004 February 2004 February 2004 April 15, 2004 JULY 22, 2004 AVAILABLE SURGE STORAGE CAPACITY 3000 EMERGENCY SURGE STORAGE CAPACITY 2800 2400 2200 2000 1800 1600 1400 1200 1000 800 MEASURED 600 400 SURGE STORAGE CAPACITY 200 0 J F M A M J J A S O N D 2001 J F M A M J J 2002 A S O N D J F M A M J J 2003 A S O N D J 11.4-INCH STORM AVAILABLE SURGE STORAGE CAPACITY (ACRE-FEET) 2600 F M A M J J 2004 A S O N D PROJECTED SURGE STORAGE CAPACITY WITH NORMAL RAINFALL RECOMMENDED CONSUMPTION (MGD) 1.0 2800 LINED OGS-N RESERVOIR AVAILABLE 2600 LINED OGS-S RESERVOIR AVAILABLE 2200 LINED NGS-N RESERVOIR AVAILABLE 2000 DISCOUNT NCP CAPACITY DISCOUNT OGS-N STORAGE CAPACITY 1800 1600 DISCOUNT OGS-S STORAGE CAPACITY 1400 1200 PREDICTED MEASURED DISCOUNT NGS-N STORAGE CAPACITY 1000 800 600 400 100-YEAR STORM (11.4-inch rainfall) AVAILABLE SURGE CAPACITY (ACRE-FEET) 2400 200 0 J F M A M J J 2003 A S O N D J F M A M 2004 J J A S CLOSURE PLAN & POST-CLOSURE STORM ROUTING NCP NGS-N NGS-S CAP OGS-N NGS-S OGS-S SCP TOP CAP AREA FINAL COVER Grassed Surface 24” Soil Cover GYPSUM 40-mil HDPE ULTIMATE CLOSURE OF SEEPAGE COLLECTION DITCH BERMUDA GRASS AMENDED GYPSUM HDPE LINER 2.5 1 24” GRASSED SOIL COVER GYPSUM RUNOFF 80-MIL HDPE LINER GEOTEXTILE GRAVEL DRAIN COLLECTOR PIPE SEEPAGE COLLECTION DITCH COOLING / SLUDGE POND COVER 24" SOIL COVER GRASSED SURFACE 40-MIL HDPE SOIL FILL, AS NEEDED SLUDGE REINFORCEMENT PINEY POINT GYPSUM STACK CLOSURE PROJECTED CLOSURE SCHEDULE May 2006 2006-07 Completed NORTH COOLING POND OR DAP POND (NCP) SOUTH COOLING POND NORTH COMPARTMENT (SCP-N) May 2006 SOUTH COOLING POND SOUTH COMPARTMENT (SCP-S) May 2005 May 2005 Sept. 2004 OLD GYPSUM STACK-NORTH (OGS-N) OLD GYPSUM STACK-SOUTH (OGS-S) Completed May 2005 NEW GYPSUM STACK-SOUTH (NGS-S) May 2006 NEW GYPSUM STACK-NORTH (NGS-N) PINEY POINT GYPSUM STACK CLOSURE CLOSED SYSTEM CIRCA CY2006 NORTH COOLING POND OR DAP POND (NCP) NEW GYPSUM STACK-NORTH (NGS-N) OLD GYPSUM STACK-NORTH (OGS-N) SOUTH COOLING POND (SCP) OLD GYPSUM STACK-SOUTH (OGS-S) NEW GYPSUM STACK-SOUTH (NGS-S) STORAGE CAPACITY IN STACK COMPARTMENTS Compartment Current Capacity, Lined Reservoir Capacity, MGal MGal Gained Storage, MGal NGS-N 125 270 + 145 OGS-S 110 155 + 45 OGS-N 145 240 + 95 SUBTOTAL 380 665 + 285 NGS-S 300 600 + 300 680 1,265 + 585 TOTAL Process Water Management Proactive Pay Me Now! Process Water Management Reactive Pay Me Later! RECOMMENDED CONSUMPTION AUGUST 2004 1.0 MGD OCTOBER 2006 0.5 MGD DECEMBER 2006 0.3 MGD PROJECTED WATER INVENTORY WITH NORMAL RAINFALL RECOMMENDED CONSUMPTION (MGD) 1.0 0.5 0.3 3600 1000 LINED OGS-N RESERVOIR AVAILABLE 2800 SOIL-BENTONITE CUT-OFF WALL 2400 800 MEASURED 2000 RECLAIM NGS-S AND SLOPES BETWEEN OGS AND NGS 600 RECLAIM OGS EXTERIOR SLOPES AND NGS-N WEST SLOPE 400 1600 1200 RECLAIM SCP-S, SIDE SLOPES OF NGS AND SEEPAGE DITCH AROUND NCP 800 200 400 PREDICTED FREE WATER INVENTORY 0 J F M A M J J 2003 A S O N D J F M A M J J 2004 A S O N D J F M A M J J 2005 A S O N D J F M A M J J 2006 A S O N D 0 WATER INVENTORY (MGAL) WATER INVENTOTY OR STORAGE CAPACITY (ACRE-FEET) 3200 MAKE-UP OF WATER TO BE CONSUMED THROUGH SEPTEMBER 2006 Current Water Inventory 160 MGal Pore Water Drainage 360 MGal Net Precipitation 255 MGal (Assuming Normal Rainfall) TOTAL TO BE CONSUMED 775 MGal WE NEED TO STAY THE COURSE FOR TWO MORE YEARS ………….. ……………... IN ORDER TO AVOID ANOTHER EMERGENCY