Geomorphic Principles Applied to Reclamation at Navajo Mine
BHP Billiton Navajo Mine Mine Design Group May 20, 2014
Contents
C. Brandt, Production Planner, Mine Design Group, May 2014 Slide 2
• History of New Mexico Coal
• Regional Topography
• New Mexico Coal Geomorphic History
• Navajo Mine Operation
• Navajo Mine Geomorphic Reclamation
– Design Objectives
– Past
– Present
– Future
• Acknowledgements
Overview • The San Juan and Navajo coal mines are
located near Farmington, New Mexico and supply two different local coal fired power plants.
• San Juan: – Underground longwall operation – 100% owned by BHP Billiton – Annual production of 6-8 million tons to
San Juan Generating Station – Current Contract through 2017
• Navajo: – Open-cut dragline operation with coal
supplied by railroad to the Four Corners Power Plant
– Annual production of 7-9 million tons through December 2013
– Annual Production post June 2013 approximately 6 million tons
Asset location map
New Mexico
Albuquerque
San Juan Mine
Navajo Mine
New Mexico Coal: Overview
Farmington Office
Slide 3 C. Brandt, Production Planner, Mine Design Group, May 2014
SHIPROCK
UTE MOUNTAIN UTE INDIAN RESERVATION
SAN JUAN RIVER
LA PLATA RIVER
ANIMAS RIVER
COLORADO NEW MEXICO
AZ
NAVAJO INDIAN
RESERVATION
NAVAJO LEASE BOUNDARY
New Mexico Coal • La Plata Mine • San Juan Mine • Navajo Mine • Farmington Office
SAN JUAN MINE
BHP Billiton New Mexico Coal
NAVAJO MINE PERMIT AREA
FOUR CORNERS POWER PLANT
SAN JUAN GENERATING STATION
FARMINGTON
Slide 4
LA PLATA MINE
C. Brandt, Production Planner, Mine Design Group, May 2014
Regional Topography
C. Brandt, Production Planner, Mine Design Group, May 2014 Slide 5
San Juan Mine Drainages
Navajo Mine Hosteen Area Drainages
La Plata Mine Drainages
New Mexico Coal’s Geomorphic History – La Plata Mine
C. Brandt, Production Planner, Mine Design Group, May 2014 Slide 6
Buckeye and Elk Point (Panel 5 Highwall) •Deepest final pit at La Plata Mine
•210 feet deep
New Mexico Coal’s Geomorphic History – San Juan Mine
C. Brandt, Production Planner, Mine Design Group, May 2014 Slide 7
Navajo Mine Overview
• Operations began in 1963 • Approximately 6 million tons of annual
production • Delivered quality of
‒ 8,700 BTU/lb
‒ 23% Ash
‒ Sulfur < 1% • Sole supplier to Four Corners Power
Plant (FCPP) • Owned by the Navajo Transitional
Energy Company, LLC (NTEC) • Operated by BHP Billiton through
December 2016 • Current coal sales contract through 2016 • Newly approved coal sales contract
between NTEC and FCPP from 2016 to 2031
• Significant resources available for future growth
Slide 8 C. Brandt, Production Planner, Mine Design Group, May 2014
Navajo Mine – Earthmoving Operations
Slide 9 C. Brandt, Production Planner, Mine Design Group, May 2014
Navajo Mine Geomorphic Design Objectives
C. Brandt, Production Planner, Mine Design Group, May 2014 Slide 10
Permit Standards • Ensured slopes in design meet permit standards • Overall slope percentages and acres comparable to the pre-mining area
Land Form • Utilized current spoils topography to increase diversification of design land forms • Improved slopes in particular areas to enhance sustainability • Defined ridges and valleys while honoring the major drainage routes • Applied geomorphic principles where practicable
Improvement In Erosion Control Structures For Sustainability • Designed down-drains for a 100 year 6 hour storm event • Reduced the need for terraces and down-drains in final reclamation
Navajo Mine Past Geomorphic Reclamation
C. Brandt, Production Planner, Mine Design Group, May 2014 Slide 11
Chinde Main Channel and Chinde Branch 2 Geomorphic Reclamation
Navajo Mine Present Geomorphic Reclamation
C. Brandt, Production Planner, Mine Design Group, May 2014 Slide 12
Tributary Channel
Challenges
C. Brandt, Production Planner, Mine Design Group, May 2014 Slide 13
FSC revision design challenges include:
• Working towards an overall balanced design surface while maintaining the material balance in the specific pit areas
• Reducing down drains along final pit tie-in areas
• Tying into previously reclaimed areas and drainages
• Managing the final pit reclaimed channel drainage grades
• Integrating geomorphic principles into an area where this type of reclamation was not previously planned
Area 2 Post-Mining Topography
C. Brandt, Production Planner, Mine Design Group, May 2014 Slide 14
Triangulation using Vulcan of the Area 3 Post-mining topography. Note the final dragline pits and spoil peaks.
Area 2 FSC – Hosteen/Yazzie Pits
Slide 15
Previous FSC Revised FSC
C. Brandt, Production Planner, Mine Design Group, May 2014
10’ Contours 5’ Contours
Area 2 FSC – Barber Pits
Slide 16
Previous FSC Revised FSC
C. Brandt, Production Planner, Mine Design Group, May 2014
10’ Contours 5’ Contours
Predicted Sediment Yields
C. Brandt, Production Planner, Mine Design Group, May 2014 Slide 17
Area 2 Predicted Sediment Yields Previous Design New Design Pre-mine=31,293 tons Pre-mine=31,845 tons Post-mine=18,926 tons Post-mine=19,491 tons Decrease in sediment yield of 12,367 tons
Decrease in sediment yield of 12,354 tons
Drainage Density Comparisons
C. Brandt, Production Planner, Mine Design Group, May 2014 Slide 18
Chinde Drainage Density Pre-mine drainage density Chinde Arroyo – 1.4 miles/sq. mile for entire drainage area and 2.8 miles/sq. mile for area
disturbed by mining Previous Drainage Density Design – 4.7 miles/sq. mile Revised Drainage Density Design – 4.6 miles/sq. mile Hosteen Drainage Density Pre-mine drainage density Hosteen Arroyo – 3.18 miles/sq. mile for entire drainage area and 2.8 miles/sq. mile for area
disturbed by mining Previous Drainage Density Design Hosteen Arroyo – 6.1 miles/sq. mile Revised Drainage Density Design Hosteen Arroyo – 5.2 miles/sq. mile Barber Drainage Density Pre-mine drainage density Barber Arroyo – 1.75 miles/sq. mile for entire drainage area and 1.46 miles/sq. mile for area
disturbed by mining Previous Drainage Density Design Barber Arroyo – 6.7 miles/sq. mile Revised Drainage Density Design Barber Arroyo – 5.3 miles/sq. mile South Barber Drainage Density Pre-mine drainage density South Barber Arroyo – 5.93 miles/sq. mile for entire drainage area Previous Drainage Density Design South Barber Arroyo – Barber and South Barber were previously combined Revised Drainage Density Design South Barber Arroyo – 5.6 miles/sq. mile
Channel Grades
C. Brandt, Production Planner, Mine Design Group, May 2014 Slide 19
Chinde
Previous FSC – 0.76% slope
Revised FSC – 0.91% slope
Hosteen
Previous FSC – 1.43% slope
Revised FSC – 0.80% slope
Barber
Previous FSC – previous drainage combined into South Barber Channel
Revised FSC – 0.41% slope
South Barber
Previous FSC – 0.91% slope
Revised FSC – combined with Barber Channel
FSC Slope Distribution by Area
Percent
Area 2 AOC PRE Variance 0-2.9% 26.9% 34.9% -8.0% 3-5.9% 28.3% 27.6% 0.7% 6-8.9% 20.4% 14.3% 6.1% 9-11.9% 11.6% 8.4% 3.2% 12-14.9% 6.6% 5.1% 1.5% 15-19.9% 4.1% 4.3% -0.2% > 20.0% 2.2% 5.5% -3.3% Total 100% 100%
Acres
Area 2 AOC PRE Variance 0-2.9% 1,579 2,047 (467.6) 3-5.9% 1,660 1,622 38.5 6-8.9% 1,198 838 360.0 9-11.9% 679 493 186.0 12-14.9% 387 297 89.5 15-19.9% 240 251 (11.3) > 20.0% 126 321 (195.2) Total 5,870 5,870
Previous FSC Slope Distribution by Area
Revised FSC Slope Distribution by Area Percent
Area 2 AOC PRE Variance 0-2.9% 28.8% 34.9% -6.1% 3-5.9% 31.4% 27.6% 3.8% 6-8.9% 18.9% 14.3% 4.6% 9-11.9% 10.0% 8.4% 1.6% 12-14.9% 5.5% 5.1% 0.4% 15-19.9% 3.5% 4.3% -0.8% > 20.0% 1.9% 5.5% -3.5% Total 100% 100%
Acres
Area 2 AOC PRE Variance 0-2.9% 1,690 2,047 (356.9) 3-5.9% 1,846 1,622 223.7 6-8.9% 1,110 838 271.6 9-11.9% 587 493 93.9 12-14.9% 321 297 23.2 15-19.9% 204 251 (47.6) > 20.0% 113 321 (208.4) Total 5,870 5,870
Slide 20 C. Brandt, Production Planner, Mine Design Group, May 2014
Previous FSC Slope Histogram
26.9% 28.3%
20.4%
11.6%
6.6%
4.1% 2.2%
34.9%
27.6%
14.3%
8.4%
5.1% 4.3% 5.5%
0%
5%
10%
15%
20%
25%
30%
35%
40%
0-2.9% 3-5.9% 6-8.9% 9-11.9% 12-14.9% 15-19.9% > 20.0%
Dis
trib
utio
n
Slope Range (% Slope)
Figure 12.3-2 Area 2 Slope Histogram
FSC Pre-mine
Slide 21 C. Brandt, Production Planner, Mine Design Group, May 2014
Revised FSC Slope Histogram
28.8%
31.4%
18.9%
10.0%
5.5% 3.5%
1.9%
34.9%
27.6%
14.3%
8.4%
5.1% 4.3% 5.5%
0%
5%
10%
15%
20%
25%
30%
35%
40%
0-2.9% 3-5.9% 6-8.9% 9-11.9% 12-14.9% 15-19.9% > 20.0%
Dis
trib
utio
n
Slope Range (% Slope)
Figure 12.3-2 Area 2 Slope Histogram
FSC Pre-mine
Slide 22 C. Brandt, Production Planner, Mine Design Group, May 2014
Benefits
Slide 23
FSC revision design benefits include:
Achieved overall material balance
‒ North pit areas balance
‒ South pit areas balance
Increased reclamation productivity
Overall land form diversity has been improved
Removed terraces in certain areas
Changed land form slopes in areas of concern from convex to concave
Removed a total of 4 down drains from final reclamation
Applied geomorphic principles to increase diversity and sustainability
Overall decrease in the modeled sediment yield
C. Brandt, Production Planner, Mine Design Group, May 2014
Acknowledgements
C. Brandt, Production Planner, Mine Design Group, May 2014 Slide 24
Tim Ramsey, Superintendant of Compliance and Reclamation, BHP Billiton, Farmington, NM 87402
Leonard Raymond, Civil P.E., BHP Billiton, Farmington, NM 87402
Brent Musslewhite, Manager Environmental Execution, BHP Billiton, Farmington, NM 87402
Steve Perkins, Superintendent Permitting & Technical Services, BHP Billiton, Farmington, NM 87402
Daphne Place-Hoskie, Superintendent of Haulage, BHP Billiton, Farmington, NM 87402
Ron Van Valkenburg, Contractor
GEOMAT, Contractor, Farmington, NM 87402
Bibliography – Need to Update
C. Brandt, Production Planner, Mine Design Group, May 2014 Slide 25
Slide 6: Place-Hoskie, Daphne (2009). Geomorphic Reclamation at BHP Billiton’s New Mexico Coal-Successes, Challenges & Future (Slides 11 and 12). Retrieved from internal network.
Slide 7: Place-Hoskie, Daphne (2009). Geomorphic Reclamation at BHP Billiton’s New Mexico Coal-Successes, Challenges & Future (Slide 4). Retrieved from internal network.
Slide 5: Place-Hoskie, Daphne (2009). Geomorphic Reclamation at BHP Billiton’s New Mexico Coal-Successes, Challenges & Future (Slides 14 and 18). Retrieved from internal network.
Slide 11: Place-Hoskie, Daphne (2009). Geomorphic Reclamation at BHP Billiton’s New Mexico Coal-Successes, Challenges & Future (Slide 15). Retrieved from internal network.
Carlson Software (2012). Carlson Natural Regrade Program. Maysville, KY.