8
are typically conducted as part of routine environmental
groundwater sampling programs, often with small, special-
ized hand-held probes that can tolerate hot water.
Water has to be isolated from the atmosphere and
cooled to measure DO.
These data can then be examined to determine the
likely corrosion regime (acidic, neutral and low-salinity or,
neutral and high salinity) and estimate expected corrosion
rates. Water quality will be ranked as non-reactive, moder-
ately reactive, or severely reactive based on the results.
The following parameters should be analyzed at several
different testing locations in various lithologies/structures
to be sent to labs for analysis: Elements and compounds
such as HCO3 (mg/L), Ca (mg/L), Cu (mg/L), Fe (mg/L),
K (mg/L), Mg (mg/L), Na (mg/L), Zn (mg/L), Cl (mg/L),
NO3 (mg/L), and SO42- (mg/L)
Recommendations for Bolt testing requirements based
on Corrosion:
• C1–C3: Non-reactive actions: None, continue bi-
annual inspections.
• C4: Moderately reactive actions: Pull test bolts bi-
annually to check capacity. Target 3 bolts per 15’ of
development. C5–C6 Severely reactive actions: Pull
test bolts quarterly to check capacity. Target 3 bolts
per 15’ of development
CURRENT CORROSION PROGRAM
OUTLINE
The current corrosion program is based on the limited
history and experiences occurrences experienced form the
68L, with high sulphides, and abundant corrosive waters
developed over the past 6–7 years. Based on testing sum-
marized in this report, the following have become evident:
TPL2(68L)
Figure 13 is a plan map of the 68 L showing the corrosion
damage extents using Corrosion level classification system.
Because of the recent bolt failures, and past testing showing
inadequate encapsulation near the collar, any temporary
rehab bolting, especially with jacklegs will eliminate using
resin cartridges, and use pumpable resin. For permanent
long-range support, a resin injection system is to be used to
insure full encapsulation for weak and highly veined rock
with high moisture content.
Ground Support System: Element longevity
The Ground Support System (GSS) used at Resolution
is primarily based on rock mass classification systems like
RMR (Bieniawski,1989) and Q system (Grimsted and
Barton,1993). The primary corrosive elements as ground
control elements currently in use include resin rebar bolts,
MAI hollow bolts, and cable bolts. Of course, this includes,
nuts, plates and accessory Occasional split sets are also uti-
lized to hold in place wire mesh. Fibercrete or shotcrete
is also used. The strategy going forward is to categorize
the corrosion protection based on the ground conditions
encountered versus the expected amount of corrosion in
each category
Full encapsulation of black steel for the entire length of
the bolt ranks high on the list to ensure bolt protection, but
the next step for long term black steel,, several other options
have been as a longer term alternative including epoxy and
thermoplastic. Figure 14 is a preliminary estimate of black
steel and steel with corrosion coatings longevity based on
total sulphide by weight percent.
CORROSION STRATEGIES
The major corrosion mitigation strategies are subdivided as
follows:
1. Full encapsulation of bolts in the entire drill hole
with resin (no voids or partial fills, especially near the
collar).
2. Coating options for ground support components
(bolts, plates, nuts, mesh, accessories).
3. Bolt types and material types for longer duration in
corrosive environments (fiberglass, stainless steel)
4. Shotcrete admixtures for corrosion protection and
acid damage.
5. Surface coating for external wire mesh and shotcrete
for rust protection.
Figure 13. Corrosion Plan Map of TPL2(68L) based on
Hadjigeorgiou and Dorian, 2013 corrosion classifications
are typically conducted as part of routine environmental
groundwater sampling programs, often with small, special-
ized hand-held probes that can tolerate hot water.
Water has to be isolated from the atmosphere and
cooled to measure DO.
These data can then be examined to determine the
likely corrosion regime (acidic, neutral and low-salinity or,
neutral and high salinity) and estimate expected corrosion
rates. Water quality will be ranked as non-reactive, moder-
ately reactive, or severely reactive based on the results.
The following parameters should be analyzed at several
different testing locations in various lithologies/structures
to be sent to labs for analysis: Elements and compounds
such as HCO3 (mg/L), Ca (mg/L), Cu (mg/L), Fe (mg/L),
K (mg/L), Mg (mg/L), Na (mg/L), Zn (mg/L), Cl (mg/L),
NO3 (mg/L), and SO42- (mg/L)
Recommendations for Bolt testing requirements based
on Corrosion:
• C1–C3: Non-reactive actions: None, continue bi-
annual inspections.
• C4: Moderately reactive actions: Pull test bolts bi-
annually to check capacity. Target 3 bolts per 15’ of
development. C5–C6 Severely reactive actions: Pull
test bolts quarterly to check capacity. Target 3 bolts
per 15’ of development
CURRENT CORROSION PROGRAM
OUTLINE
The current corrosion program is based on the limited
history and experiences occurrences experienced form the
68L, with high sulphides, and abundant corrosive waters
developed over the past 6–7 years. Based on testing sum-
marized in this report, the following have become evident:
TPL2(68L)
Figure 13 is a plan map of the 68 L showing the corrosion
damage extents using Corrosion level classification system.
Because of the recent bolt failures, and past testing showing
inadequate encapsulation near the collar, any temporary
rehab bolting, especially with jacklegs will eliminate using
resin cartridges, and use pumpable resin. For permanent
long-range support, a resin injection system is to be used to
insure full encapsulation for weak and highly veined rock
with high moisture content.
Ground Support System: Element longevity
The Ground Support System (GSS) used at Resolution
is primarily based on rock mass classification systems like
RMR (Bieniawski,1989) and Q system (Grimsted and
Barton,1993). The primary corrosive elements as ground
control elements currently in use include resin rebar bolts,
MAI hollow bolts, and cable bolts. Of course, this includes,
nuts, plates and accessory Occasional split sets are also uti-
lized to hold in place wire mesh. Fibercrete or shotcrete
is also used. The strategy going forward is to categorize
the corrosion protection based on the ground conditions
encountered versus the expected amount of corrosion in
each category
Full encapsulation of black steel for the entire length of
the bolt ranks high on the list to ensure bolt protection, but
the next step for long term black steel,, several other options
have been as a longer term alternative including epoxy and
thermoplastic. Figure 14 is a preliminary estimate of black
steel and steel with corrosion coatings longevity based on
total sulphide by weight percent.
CORROSION STRATEGIES
The major corrosion mitigation strategies are subdivided as
follows:
1. Full encapsulation of bolts in the entire drill hole
with resin (no voids or partial fills, especially near the
collar).
2. Coating options for ground support components
(bolts, plates, nuts, mesh, accessories).
3. Bolt types and material types for longer duration in
corrosive environments (fiberglass, stainless steel)
4. Shotcrete admixtures for corrosion protection and
acid damage.
5. Surface coating for external wire mesh and shotcrete
for rust protection.
Figure 13. Corrosion Plan Map of TPL2(68L) based on
Hadjigeorgiou and Dorian, 2013 corrosion classifications