Karst Features within the
Bedrock at the Hidden Quarry
Site
GET Council Meeting
CRC Scientific Review Committee
Michael Venhuis and Bill Hill
March 17th 2014
Karst Analysis – Harden
Environmental Services
“A karst environment is not present in the area proposed to be mined by the Hidden Quarry.”
Harden Environmental Services Letter
September 5th 2013
Karst Features
Bedrock
• Dissolving dolomite
• Fractured rock
• Porous
• Cavities/Caves/Trenches
• Fissures
Landscape
• Sinkholes/Wetlands
• Disappearing streams
Why Worry about Karst Features
within Hidden Quarry Bedrock?
•
•
•
•
Hazardous –unstable bedrock!!!
Unpredictable blasts (underwater?) due to complex rock
structure.
– Flyrock potential.
– Building damage
– Injury and fatalities
Increased potential for groundwater contamination (Walkerton
O157:H7 E.coli outbreak).
Modeling of groundwater flow requires significant understanding
of karst geology.
MNDM Karst Map of Southern Ontario
MNDM Karst Map of Southern Ontario - Enhanced
MNDM Karst Map of Southern Ontario – Rockwood Area
Geological Map of Southern Ontario – Rockwood Area
Schematic of Bedrock/Soil
Karst
Karst
Conservation Area Amabel - Dolomite
HQ
No Karst?
Blue Springs
Karst Analysis – Harden
Environmental Services
Test Format
• 7 bore holes within site
that penetrate bedrock
• June 2013 – 150 mm
borehole with camera
and velocity meter
(M15)
CRC Due Diligence
Borehole testing
• Not enough boreholes!
• 1 borehole/10 football fields.
• Borehole data suggest karst features cannot
be ruled out (M2, M4, M15 shown here)
CRC Due Diligence
Harden Borehole (M2) testing
CRC Due Diligence
“Vuggy Porosity”
A more recent view to emerge has been that the
defining characteristic of karst aquifers is not so
much the apertures but rather the connectivity of the
solutionally-enlarged fractures, and that channels
(solutionally-enlarged fractures that may be less
than 1 mm in diameter) play an important role as
well as conduits (Huntoon, 1995; Worthington,
1999).
- From “Karst Investigations at the Proposed South
Quarry Extension” – Worthington Groundwater:
February 2009.
CRC Due Diligence
Harden Borehole (M4) testing
CRC Due Diligence
Harden Borehole (M15) testing
Other Stakeholders (MOE)
Agree!
CRC Due Diligence
Sinkholes/Disappearing stream
Summary of Current Data
Hidden Quarry
Bedrock
Karst
(CRC)
No Karst
(JDCL)
Potential Karst mapping by
MNDM
Fractured rock
Boreholes – suspect Karst
Dissappearing stream
Sinkholes
Stakeholder query
Only 1 borehole result
supports no Karst statement.
Summary and Request to
Council
•
•
•
•
Karst study significantly flawed.
Karst features are present at the site.
Involve other stakeholders in further evaluation.
Review of the groundwater model by a
groundwater modeler with fractured rock/karst
geology knowledge (Burnside request)
THANK YOU!
Concerned Residents
Coalition Rockwood
www.crcrockwood.org