Joe Riddell, M.Sc., P.Geol. Dylan King, P.Geol. WaterTech 2014

Banff Alberta, April 11, 2014

Improved Analysis & Stakeholder Engagement using 3-D Conceptual Site Models

Agenda

1 Overview & CSM Development

2 Examples of CSM Development and Outcomes

3 Conclusions and Questions

Overview & Development of Conceptual Site Models (CSM)

1

CSM – What is it? Compilation of existing site information • Previously collected geological, geotechnical,

hydrogeological, and analytical data for soil/groundwater

• Compiled into a 3D Geomodel of the site • Geological structure, hydrogeologic regime and

key physical processes are characterized

Tells the story of what we know • Presents our current understanding of site

conditions, including contaminant distribution

CSM – Why build a CSM? Allows multiple hypotheses to be evaluated • Data gaps can be systematically filled • Added value and cost savings • Powerful data synthesis tool • Helpful in stakeholder communication with

client/regulators for approvals or scope changes • Very useful for long-term sites and monitoring Valuable reconnaissance for field staff • Field staff starts with salient geological features

and an understanding of the setting • Drilling prognoses • Iterative, on-the-fly improvements to CSM can be

made during drilling program

CSM Development & Challenges Data Normalization • Difficult to normalize data from different sources • Different data types • Incomplete data sets (i.e., lacking well attributes) Requires Experienced Analyst • Earth scientist with understanding of sedimentary

processes, stratigraphic correlations & hydrogeological processes

• Requires advanced supporting software tools

CSM Development Workflow

Data Gathering

CSM Development

Field Program Numerical Model

Statement of problem and objectives

Data Formatting

Interpretation

Data Gap Analysis

• More efficient iteration (on-the-fly)

• File management • Use of other geo-

spatial platforms

Data Compilation and Normalization

Un-normalized Data: Iterative CSM Development Challenges with existing site information • 3-D geological software still needs to be guided • Several technologists logging core • Heterogeneity • Data gaps Skilled operator required • Pre-interpretation • Start simple cross sections > • Normalize data to a consistent CSM (hydrostrat) • Implement CSM in 3-D geological modeling

software

CSM Development and Outcomes

2

Example 1 - Desktop Studies Hydrogeological Issues in Residential Development

• Foothills Subdivision • Water ingression into homes • Previous Geotechnical Study

(during dry period): • Water table configuration • Wetland area & shallow

groundwater issues such as local discharge areas (springs)

• Geology promotes interflow • Toe-slope position & large catchment • Mapped glacial melt water channels • Temporal variability & monitoring • Easily determined during planning

12x

Example 2 – Production Well Installation and Optimization • Concrete Plant • No municipal water supply • Preliminary model (AWWID) • Horseshoe Canyon Fm. • Possible buried channel

deposits • Possible productive bedrock

intervals • Preliminary model with

public water well data • Identification of potential

drilling targets, static WLs, surrounding pump intake and screened interval analysis

• Ongoing model updates during drilling

• Successful production well installation and stakeholder engagement

Example 3 – Use of CSM for hydrocarbon delineation • Capitol Region site

with HC impacts Bring readily available information into model: • Site topography • 72 Borehole logs • Digital air photo of site • Limited data from

AESRD & AGS (raster, vector & even tabular mapping data)

• Minor analytical soil and GW Data from historical reports

Un-normalized Data • Verbatim initial

plotting of the data in a 3D environment

• Plots all observed lithologies on site

• Geologist then works through each record to normalize lithologs with a unified model of site conditions

• Records are re-interpreted On-the-fly iterative process

Generation of Geological volumes • User specifies:

• Stratigraphic rules • Hydrostratigraphic

framework

• Model generates bounding surfaces and volumes of normalized layers in the CSM

• Build water table surface based on monitoring data

Data Gap Program • a) Based initially on soil

vapour screening to produce a conservative contaminated soil volume

• b) View proposed boreholes within context of geology, hydrostratigraphy, and estimate of contaminated Soil volume to accurately delineate a more accurate, refined volume for remediation scoping

a)

b)

Example 4- Solution Mining Project EA Proposed development includes infrastructure, production and injection wells, brine pond and tailings management area (TMA)

Assessment objectives were to

1. Increase understanding

2. Evaluate risk

3. Mitigate risk

Development of a 3D Conceptual Site Model was chosen as an efficient way to synthesize the data to understand groundwater quantity and quality and to evaluate and mitigate potential interactions

Hydrogeology • Base of model is a thick

marine shale aquitard at 100-200 m BGL

• Empress group preglacial or glacial sand and gravel in a large buried channel

• Overlain by a series of glacial drift formations consisting of layered sand aquifers and till aquitards

• Five till units containing six mapped sand and gravel aquifers

Period Stratigraphy Lithology

Group Formation Unit or Member

QUA

TERN

ARY

Sask

ato

on

Surficial Stratified Deposits

Aluvium Silt, Sand, Gravel Clay, Silt, Sand

Silt, Sand, Gravel Clay, Silt, Sand

Haultain Silt, Sand, Gravel Clay, Silt, Sand

Silt, Sand, Gravel Clay, Silt, Sand

Battleford Till

Gravel, Sand, Silt, Clay

Floral

Upper Till

Riddell (Middle) Gravel, Sand

Lower

Till

Gravel, Sand, Silt, Clay

Till

Suth

erla

nd

Warman Till

Gravel, Sand, Silt, Clay

Dundum

Upper Till

Gravel, Sand, Silt, Clay

Lower

Till

Gravel, Sand, Silt, Clay

Till

Mennon Upper

Till

Gravel, Sand, Silt, Clay

Lower Till

Emp

ress

Upper Gravel, Sand, Silt, Clay (Proglacial)

Lower Chert and Quartzite Sand on Gravel

(Preglacial) C

RETA

CEO

US

Mon

tana

Pierre

Odanah Member sand and silt

"Lower" Odanah Member

silt and clay

Millwood Member

silt and clay

Pembina Member

silt and clay

Gammon Member

silt and clay

Hydrogeological Data

Data gathering, review and synthesis. 186 - water well records with e-logs to determine lithologies but additional information to make picks was not available (Carbonate content, preconsolidation pressure)

8 - regional groundwater studies

9 - Shallow groundwater wells in the TMA

• Similar initial steps • Development is

cumbersome and time consuming

• No reinterpretation on the fly • Many iterations of the

process

Traditional CSM Development

grid surfaces individually

grid math to create isopachs

cut cross sections and fence diagrams for pseudo 3D analysis

grid potentiometric surfaces and iso-concentration contours

create blanking files

Development in 3D Software Environment

• Stratigraphic picks form collar table for import into the model

• Create first cut at surface generation

Development in 3D Software Environment

• Dynamic visualization to identify gross anomalies

• Identify discrepancies between model and regional studies,

• Reinterpret e-log as necessary

Development in 3D Software Environment • Add additional e-log interpretation to fill gaps and reinterpret

on-the-fly • Make manual adjustments to surfaces based on depositional

interpretation and stratigraphic principles until satisfied with model

• Add aquifer parameters, hydrochemical & potentiometric data

Numerical Model • Export of 3D CSM directly to

FEFLOW or MODFLOW

• Detail groundwater flow and simulate contaminant transport scenarios

• Collaboration and communication between project hydrogeologist and modeler

• Design meaningful monitoring and mitigation

Project Mitigation based on CSM and Numerical Model • Monitoring network design – appropriate spacing depths

and coverage • Perimeter ditch design around TMA – design depth • Slurry Cutoff Wall Design – appropriate depth based on

contaminant transport modeling predictions

Example 5 – Coal Mining Project EA • Proposed development includes two open pit areas, waste

rock disposal area in a mountainous environment with complex structural geology

• CSM forms framework for the baseline assessment of groundwater flow patterns, quantity and quality

• Numerical model to evaluate interactions between the project, groundwater and surface water resources

• CSM used to develop effective monitoring and mitigation measures to limit potential impact

Project Background • Limited sub-surface data

• Coal exploration picks (x’s)

• Stantec boreholes (green) and hydraulic testing

• Large domain required for EA (limit BC effects)

• Scanned and geo-referenced structural and bedrock geology Maps

• Drift thickness data

• LIDAR of mine site & DEM

• Mine progression plan

• Literature

Geological Interpretation Fenced lines along structural axes to extrapolate the geology of a boss layer (important aquifer)

Assumes hydrostratigraphic column with constant unit thickness

Fencing & proposed Boreholes

• Use high density data and work away from “known” geology to generate key hydrostraitgraphic layer

• Fence lines positioned along fold axes, and polylines used to infer geology using structural data, and ~ 200 proposed BHs were added

• Marked boreholes with the elevation where polyline crosses proposed BHs to get structural geological elevation picks (approx. 200) Regional Anticline

Regional Syncline

Regional Anticline

Building Hydrostratigraphy • Gridded picks to generate surfaces outside of 3-D environment • Build depositional surfaces with hydrostratigraphic column & True Vertical

Thickness offset calculations • Grid math to add the vertical offset to boss layer (Blue) elevation • Erosional deposits specified based on drift thickness and surface

mapping of till and alluvium/colluvium

Final Geomodel for Export to FEFLOW • Aquifers in yellow, aquitards in brown, and surficial deposits • Challenging computation with large, high resolution domain • Send ready–made FEFLOW grid to modeling team for baseline

assessment • Change topography as mine life cycle progresses to evaluate mine pit

inflows and potential impacts

Conclusions 3

Summary In some capacity, our role as a consultant parallels that of a 1st year Earth Science Professor… • Block models and cut-away views are the only way to

communicate the subsurface complexity to lay-people (stakeholder communication)

• Allows rapid visualization, efficient workflow to generate figures & accurate cross sections

Summary Project benefits include: • Iterative and real-time analysis and model

adjustments provides a powerful data synthesis tool • Use to optimize drilling programs and process new

data efficiently • Aids in monitoring and mitigation of potential

and/or pre-existing impacts • Opens the door for follow-up project work • Greatly reduces cost associated with developing

numerical groundwater flow models if a CSM completed at project outset

Questions?