CALGARY, Alberta (Reuters) - Enbridge Inc
could begin replacing a section of damaged Michigan pipeline as
early as Monday evening, but it still has no estimate on when
it could restart the line, which ruptured last month and
spilled more than 800,000 gallons of oil.

Enbridge removed a 50-foot section of the line last Friday,
shipping it to regulators in Washington D.C., who will examine
a gash nearly 5-feet long in the pipe to determine the cause of
the rupture.

The company is ready to replace the damaged section but is
far from restarting shipments on the line, which normally
carries 190,000 barrels of Canadian crude per day to refineries
in Michigan, Ohio, Pennsylvania and Ontario.

"We could be ready as early as this evening to start
lowering that new section in to start that repair," Pat Daniel,
Enbridge's chief executive, said on a conference call. "I can't
give an estimate, at this point, how long the repair will
take."

Once the pipe is replaced, Enbridge will have to file a
restart plan with regulators before Line 6B can be returned to
service, initially at lower than normal pressure.

The timing of the restart "dependent entirely on the
regulators' acceptance of return to service plan," Daniel
said.

The pipeline broke open on July 26 near Marshall, Michigan,
spilling crude into the Kalamazoo River system, forcing a
cleanup effort involving more than 800 workers and 105,000 feet
(32,000 metres) of containment and absorbent boom.

The spill represents one of the largest pipeline leaks in
recent U.S. history. It arguably gained increased profile
against the backdrop of the much bigger BP disaster in
the Gulf of Mexico.

Enbridge shares fell 10 Canadian cents to C$51.62 on the
Toronto Stock Exchange on Monday. The shares have fallen 0.5
percent since the July 26 spill while the exchange's benchmark
index has climbed 0.5 percent over that span.

($1=$1.03 Canadian)
(Reporting by Scott Haggett; editing by Rob Wilson)