PERMFILE57051

• Permit No: M1999002
• IBM Index Class Name: Permit File
• Doc Date: 6/18/1999
• Doc Name: OBJECTORS EXHIBITS
• Media Type: D
• Archive: No

Brinelreld Subsidence at Windsor, Ontario•
unconsolidated material ranges between 85 and
104 feet within the area subject to gradual subsid-
ence prior to the formation of the sinkhole.' A
thickness in excess of 99 feet [vas encountered in
only hvo oC the twenty wells for which data are
available, and the log of only one of them indicates
a thickness of less than 91 feet. These data suggest
that the thickness of the clay underlying the sub-
siding azea, was, with minor exceptions, behveen
91 and 99 feet.
The Pleistocene sediments are underlain by sedi-
mentary rocks of Devonian and Silurian age (Bays
1954, Caley 1945 and Landes 1945)..4s shorn in
Figure 1, the uppermost part of this sedimentary
series consists of several hundred feet of limestone,
referred by Bays (195.1) to the Norfolk (Canada)
or Dundee-Detroit River (U.S.) Formation. On the
basis of drilling records, Bays described the forma-
tion as follows: "The Norfolk is ... a predomi-
nantly brown limestone 335 to 350 feet thick.
Large yields of water, and mud losses during dril-
ling, in the Norfolk. indicate it is extensively
jointed and fractured."
The Norfolk Limestone rests on sandstone be-
longing to the Syh'ania Formation of Devonian
age. According to Bays, "The sandstone is usually
in two benches split by a gray and brown lime-
stone. The three units total 175 to 200 Eeet in
thickness. Cementation in the Sylvania is highly
variable; some beds are well cemented tith carbon-
ate or silica and others are very loose."
Carbonate strata of Upper Silurian age, com-
monly about 300 feet in total thickness, underlie
the Sylvania. Their general relationships suggest
that they belong to the Bass Island Formation, en-
countered in brine wells in the Devoit area. In that
region, the uppermost t~vo hundred feet of the for-
mation is reported to be sound, strong and compe-
tent, and capable of bridging cavities ~~ith a span of
several hundred feet without any indications of
sloping (Terzaghi 1950). This observation indicates
that the joints are in general far apart, the blocks
behveen joints well interlocked, and the bond
across bedding planes fairly strong.
The uppermost evaporite bed was commonly en-
countered in the Sandwich wells at depths ranging
between 975 and 1000 feet. This bed, together
with the underlying approximately 800 feet of
dolomite, shale, gypsum, anhydrite and sal[, has
been referred to the Salina Formation of Silurian
age.
The uppermost bed of salt is generally 10 to 30
feet thick. Separated from this bed by a Ee~v tens
of feet of carbonate rock, the underlying salt
CLAY, SILT PLEISTOCENE
NORFOLK- 100
DUNDEE- p00
DETROIT
RIVER
LIMESTONE 300 z
400 0
w
SYLVANIA 500 °
SANDSTONE
600
BASS
ISLAND
DOLOMITE
700
B00
800
- i
1000 UppER
SALTS
1100 f ~
h

1200 1QTfTTTCf~1CET a
h W

1300 ~
o
_
~ Y
J
o z

1400 ~-
o a N
LOWER =
1500. SALTS

~ ,
i
1600 -
-
Figure 1. Typical section, Sandwich brine field.
2. Estimates of thickness of Pleistocene deposits ue based on length
of dris~c pipe, consisting of l0. or 12y>•in. asing, which was, accord•
ing to Dr. Bays (195J) "set on the bedrock or into it a few feet."
Hence the data may ezaggente the thickness of the clay by a tow
feel