Using Weep Berms to Control Water Quality by Richard Warner and Greg Higgins

SME/ARIESENVIRONMENTAL CONSIDERATIONS IN

ENERGY PRODUCTION

RICHARD WARNERUNIVERSITY OF KENTUCKY

GREG HIGGINS MANAGER - MIDDLEFORK DEVELOPMENT

CORP.

SEPTEMBER 23 , 2015

Using Weep Berms to Control Water Quality

Briefing Outline

Overview of Current Mining Methods Cost-effective and Environmentally-protective

Innovative Methods Utilized in OSM Experimental Practice Drill Core Strata & Screening-level Assessment Isolation of Problem Strata Design and Construct Weep Berms Re-establish Hardwood Forest (FRA) Environmental and Community Protection

MFDC – Weep Berm

Profitability and Sustainability

Companies that Successfully Implement a High-Level Sustainable Mining Operation are More Profitable than those that don’t* Be protective of your communities Be protective of your environment

Yes, cost savings and environmental and community protection can all be achieved

Investing now in such measures generates opportunities to have a license to operate in the future.

*Harvard Business School study 1992 - 2010

Completely Change Engineering Design Philosophy

Current: Gather Runoff to Central Locations Passive treatment Discharge

Needed Change: Mimic Nature - Keep Runoff Spatially Distributed Passive treatment Discharge at multiple locations Incorporate the natural environment as a secondary

passive treatment system

PROFITABLECOST SAVINGS

ENVIRONMENTAL PROTECTION

COMMUNITY PROTECTION

A Case Study: Incorporating U.S. OSM Experimental Practice on a Appalachian Surface Coal Mine

Current Mining Methods - Appalachia

Insert Greg’s 877-0179

PRESENT METHOD : Valley Fill

OSM Experimental Practice Mining Innovations

X

X

XX

X

X

X

X

Attributes Disposition

6 Valley Fills 6 Sediment Ponds 40 Bench Ponds 13,000 ft Stream Covered by

Spoil 252 ac Bonded 46 KPDES Monitoring Locations ACOE 404 Permit Water Quality Liabilities Flooding Liability Substantial Reclamation Cost Compacted Spoil with Grass

100 % Eliminated 100 % Eliminated 100 % Eliminated Zero ft Stream Loss

Reduced to Bonding 190 ac 2 KPDES Monitoring Locations Not Needed ~Forest Water Quality No Flooding Potential Minimal Reclamation Cost Multi-use Forested/Grass

Watershed

Cost Savings and Environmental Protection

$7 TO $9/COAL TON

Cost Savings

Weep Berm US OSM Experimental Practice

Weep BermEngineered Earthen Berm with Multiple

OutletsPassively Slowly Discharges to Down-gradient

Forest

StreamForest

Check Dam

Check Dam

OutletStructures

Watershed Area SedimentDitch

WeepBerm

Check Dam

L

Sediment Laden Runoff

Weep Berm

Forest

Advantages of a Weep Berm

Cost Effective to ConstructSlow Passive Seepage into Forest through Multiple

Outlets (660 – MFDC)Sedimentation in Weep Berm and Close Proximity

Forest Zero Sediment Transported to Stream

Hydrology – Mining and Reclamation Sustainability Attenuates peak flow - eliminates flooding Complete storage and infiltration of small rainfall

events (less than 1 in – design depended) Increases base flow

Water Quality - Mining and Reclamation SustainabilityReduction of specific conductivity to pre-mining levels

Reduction of selenium to pre-mining levels

Weep Berm Performance

Georgia (USA) – Construction Site - Storm Water and Sediment Control (GA DNR funded)

Georgia – 2 Construction Sites, Comparison of Weep Berm and Silt Fence ( US EPA Region IV funded)

Peru (copper and zinc mines) – Treatment of Sediment and Metals (several mines) (Newmont (2) and Antamina)

Ghana ( 2 gold mines) –Sediment and Metals (Newmont)Panama (copper) –Sediment (Minera Panama)Democratic Republic of the Congo – Sediment (Freeport

McMoran - copper)Philippines – Sediment (Xstrata – coal)KY – Passive Water Treatment (sediment, pathogens and

nutrients) – horse muck composting facility (KY USDA funded)

KY – Passive Water Treatment (sediment, pathogens and nutrients) – horse muck storage facility (privately funded)

August 2000

© Surface Mining Institute

Weep Berm - Panama

Runoff – Panama (5.5 to 6 m/yr Rainfall)

TFM – Democratic Republic of the Congo

TFM – DRC – Demonstration Weep Berm

Combination Contour Weep Berm – Grass Filter25

Excavator Weep Berm Construction(Middle Fork Development Corp.)

Weep Berm – No Rock Lens

Weep Berm with Rock Lens

Storm Containment

Seepage Through Rock Lens

MFDC – Weep Berm

MFDC – Weep Berm

MFDC – Weep Berm

EarthWorks Weep Berm Design Steps

AutoCAD drawing with 3-D polylines (topography) and mine plan

Define working areaGenerates TIN and GIS gridSelect Weep Berm control structureStart point and end point (or length)Input weep berm and rock lens parametersGenerates AutoCAD drawing and catchment

(area, Tc),cut/fill, stage-area-capacity-dischargeSeamless export to SEDCAD

Contour Weep Berm Design Using Rock Outlets for Discharge

Schematic of EarthWorks Discharge Options

EarthWorks Weep Berm Inputs

EarthWorks Rock Outlet Input Options

EarthWorks Automatic Design

Contour Weep Berm Design with Excavation - Inputs

EarthWorks Automatic Design

Seamless Export to SEDCAD

Area and TcStage-Area-Capacity-DischargeAdd CN and UHSAdd sedimentologic parametersDesign CompletedPeak flow in/outPeak stageSediment depositionTSS in/outSettleable solids in/out

How Well Do Weep Berms Work?

HydrologicalSedimentologicStabilityConductivity

Current Valley Fill - Conductivity

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

0.00

500.00

1,000.00

1,500.00

2,000.00

2,500.00

10/17/2012 11/6/2012 11/26/2012 12/16/2012 1/5/2013 1/25/2013 2/14/2013 3/6/2013

Rain

fall

(inch

)

Cond

uctiv

ity

Date

Daily Rainfall

Instantaneous Conductivity

Avg Daily Conductivity

Middle Fork – Monitoring Locations

Maximum Depth of Water – Period of Monitoring Record

Weep Berm % Time Water Discharged over Entire Monitoring Period

Weep Berm - Average EC Discharged

Middle Fork - Hydrology