The Presentation by Southwest Research and
Information Center (SRIC) and Concerned Citizens for Nuclear
TESTIMONY OF JACK PARKER - March 5, 1999.
Mr. Parker received a M.S. in Geology, Michigan Tech,
1960; a B.S. in Geological Engineering and a B.S. in Mining
Engineering, Michigan Tech, 1958. Mr. Parker is a
Registered Professional Geologist.
Mr. Parker has over 50 years of experience in problems of
mine stability in England, Canada, and the United States.
Since 1971, Mr. Parker has been self-employed as a mining
and geological consultant, specializing in practical rock
mechanics, at Jack Parker and Associates, Inc. His clients
include about 100 mining companies. Mr. Parker has worked
in several hundred mines. He is frequently called to help
solve an unexpected problem, like a roof-fall.
Mr. Parker was part of the 1991 panel of experts set up
by the DOE to give outside opinions concerning the stability
of Panel 1 after the roof-fall in the Site and Preliminary
Design Validation (SPDV) Room 1. When Mr. Parker last
visited the WIPP underground, in December of 1998, he
observed that the rooms in Panel 1 had deteriorated--
especially the roofs. The roofs were broken and supported
by roof bolts, which were themselves breaking regularly and
requiring continual replacement. Mr. Parker concluded from
his observations that the roofs were not stable and that
freshly excavated (by nature more stable) rooms should be
used for waste emplacement.
Mr. Parker defined the following terms:
Stable: standing without change, neither improving nor
Creep: gradual deformation of material under constant
stress. The material continually moves plastically.
Vertical pressure induces sideways pressure. The salt is
behaving like a fluid and flows towards zones of lowest
Fracture: squeezed salt extrudes sideways. This term is
usually applied to more brittle material, but rock salt will
do the same thing where it is not confined.
Failure: when roof beams eventually break. A failed
roof could be supported artificially, but if not supported
it will fall. In Panel 1 there is already roof failure.
The supports mask the failure, but one can see shear along
the ribs, cracks, and joints in the ceilings. Broken roof
bolts and sag in the roof are also visible.
Two convergence graphs were described. [Convergence
occurs when two or more objects approach the same point from
different directions.] Convergence graphs are used as a
tool to predict roof-falls. Figure 8 compares roof-to-floor
convergence for SPDV-1 and SPDV-2. [Both rooms eventually
had roof falls.] Figure 9 shows SPDV -1 rates per year of
convergence. Figure 8 demonstrates that different rooms
have different convergence rates. This is not unusual in
evaporite mines. [Evaporite is the sedimentary deposit
created by the evaporation of seawater.] Failure would not
occur at the same time in 2 rooms unless there was a chain
reaction. Figure 8 appears to show an annual cycle of
convergence in each of the rooms. If the cycle in Figure 8
were broken for SPDV-1 and convergence rates rose sharply
and continued to rise, Mr. Parker would predict a fall
"soon." However, graphs can be complicated by other
variables (for instance, bolting).
The failure mechanism for SPDV-1 was salt from the tops
of the pillars on each side of the unit pushing or flowing
toward the center of the room. This caused the roof to
buckle and fall. Mr. Parker would have liked to inspect
SPDV-1 and SPDV-2 after their roof falls, as well as the
other closed experimental rooms, but the DOE prohibited
access by installing a concrete barricade. For a proper
analysis of a rock-fall, it is essential to see the worst,
best, and average rooms in order to see a whole range of
WIPP is not unusual for a deep salt mine in bedded salt.
The Cayuga Mine in New York state was a salt mine that had
similar problems. In fact it had dozens of roof-falls
bigger than SPDV-1. The pillars were too big and pushed
into the roof and floor. Reducing the size of the pillars
solved the problem. Each large pillar had holes excavated
in it and then was divided into 4 smaller pillars to reduce
HOW FAR IN ADVANCE CAN A ROOF FALL BE PREDICTED? One
could probably tell with certainty a week or two in advance
of a roof-fall, maybe a month or two. Sometimes one could
predict earlier when a roof would fall, but other times
there are surprises. Because of the different roof support
systems in the different rooms there will be a differing
ability to predict failure in each room. The different
support systems mask effects that are normally used to
predict falls. The roofs have probably failed already and
are just suspended by the bolts. The DOE believes it can
predict failure 18 months in advance. Mr. Parker does not
The Hearing Officer asked if Mr. Parker could give a
percentage of confidence on when a roof would fail. Mr.
Parker answered that predictability in this science is
crude. In some mines without roof bolts and with
predictable geology, one could see a break in the
convergence curve and predict failure 3 months in advance,
but this is not always possible to see from the graphs.
CHAIN REACTION: Stress usually develops along the ribs
(sides) of a room. Those bolts along the ribs fail first.
One might or might not be able to tell whether the bolts
have failed. At this point there would probably be rock-
falls along the ribs which would be the initial signs of
failure. In some of the Panel 1 rooms the supports are tied
together with mesh and cable along the roof and down the
sides of the walls. In this case, if there is failure of
the bolts on the ribs, the stress could be transferred to
the other bolts in the support system and may create a
domino effect. Mr. Parker has seen this happen in other
MAINTENANCE: With enough money and effort one could
support a room indefinitely. Wooden cribs could slow down a
roof-fall, and if one totally backfilled a room the roof
might never fall. Waste could be recovered after a roof-
fall, but more people would be at risk and it would take
much more time and money. Bodies would be recovered after
roof-falls. Mr. Parker also testified that such a
considerable risk should not be undertaken at WIPP. At
WIPP, there are cheaper and safer alternatives to using
Figure A-4-2 from the Permit Application was shown. This
is a picture of a mined area underground. Mr. Parker stated
that conditions are much worse underground now than when the
picture was taken. The best way to handle the situation in
Panel 1 would be to not use Panel 1, excavate a new room,
stuff it with waste, and seal it. This would be more
economical and safer than the DOE's current plan.
HIGHLIGHTS OF CROSS-EXAMINATION OF JACK PARKER:
In Mr. Parker's 1991 affidavit he stated that there would
be at least 6 months of advance warning of a roof-fall. Mr.
Parker stated that the degree of prediction was different
then. Six months is enough time to evacuate personnel in
empty rooms, but if waste emplacement were being scheduled,
he would not be giving any such dates.
Immediately after a new support system is installed,
maintenance other than visual inspection is not required for
some period of time. However, a new system could not be
installed if there was a chain reaction type of failure.
Maintenance of support systems in unfilled areas of disposal
rooms could be performed if there were no unexpected chain
reactions. Mr. Parker does not know what the conditions
would be like for repairs. The DOE asked whether cost was a
factor in the decisions made to prevent roof-falls in the
Cayuga mine. It was.
Geotechnical data at WIPP is "good of a kind." Judging
from the results of the observations of the Ground Control
personnel at WIPP and their plans, Mr. Parker believes his
observations are better. Some members of the 1991 expert
panel who praised the geotechnical database for WIPP and
promoted roof support systems were probably doing so to drum
up business! However, the database could be described as
better than at most mines. Generally the mine is well
If there was sufficient time to replace all the bolts in
a roof support system, a chain reaction could be prevented.
However, Mr. Parker believes there will be need for
maintenance on the newest bolt system installed in Room 7
within the first 2 years after installation. Installation
of up to 3 sets of roof bolts has not changed the rate of
convergence significantly. The rate can still be measured
at WIPP. If the rooms at WIPP were filled within 5 years of
excavation, the design would be adequate. Mr. Parker would
not, however, recommend this design.
Based on the Figure 8 convergence graph for SPDV-2 Mr.
Parker could not have predicted when that roof would
Evidence that support systems are masking roof failure
could be such things as heads popping off the roof bolts,
bolts falling out, or rib areas falling apart while the
convergence point in the middle of the room still appeared
to behave normally. Roof bolts can fail without being
detected by visual examination when they hang up in the
drill hole. There could be more roof bolt failures at WIPP
than are detected by visual observation alone.
If waste were emplaced in a room, rock bolts could not be
replaced above the waste. A chain reaction and collapse of
the roof could take place.
A second fall into the void space of the first roof-fall
can occur anywhere from a few minutes to a few years later.
There is usually a limit to how far up a series of roof
falls will go. Since the most favorable shape for a mine
opening in rock salt is a sphere, the falls will approximate
this shape. The sphere will be the limit for the zone of
tension. At WIPP you will end up with a natural arch
interrupted by partings.
At Cayuga, the Mine Safety and Health Administration
(MSHA) closed the mine for a month after multiple roof-
falls. Mr. Parker has seen MSHA close another mine because
of instability. MSHA sometimes called in technical support
to evaluate stability problems.
Brine is pressurized in pockets 700 or 800 feet below the
WIPP site. Under similar circumstances in European mines,
even with a 700-foot distance from the mine, there have been
bursts of water and gas. The operations in Europe were more
extensive than at WIPP. The same thing is possible at WIPP,
but not probable.
METHANE GAS EXPLOSION: If there were a methane gas
explosion in the repository, personnel in active areas could
be hurt or killed. The severity of any damage would depend
on the magnitude of the explosion and the quality of panel
seals. There have frequently been methane gas explosions in
closed portions of coalmines and in a few salt and potash
mines that caused the death or injury of workers in the
active parts of the mine.
The problems at WIPP are typical and Mr. Parker has seen
similar situations in one or two dozen mines elsewhere.
When his recommendations were followed, situations