The phrase "a third bore" is grammatically correct and can be used in written English.
It can be used in contexts where you are referring to a third instance of something that is dull or uninteresting, often in a humorous or exaggerated manner.
Example: "After listening to his third bore of a story, I couldn't help but yawn."
Alternatives: "a third dull moment" or "a third tedious tale".
Proposals to solve the traffic problems have included building a third bore, constructing alternative crossings of the Thames such as the now cancelled Thames Gateway Bridge or the Silvertown Tunnel, and providing better traffic management, particularly for heavy goods vehicles.
A third bore of the tunnel, replacing the old Victorian northbound bore, was proposed by Transport Secretary Cecil Parkinson in 1989, but had yet to see any progress towards construction over a decade later.
In our last issue of the UCMP News, we mentioned the "Fourth Bore project" the construction of a fourth bore of the Caldecott tunnel, which is yielding a variety of vertebrate, invertebrate, plant, and microfossils.
A fourth bore is in the works.
A November 2011 photo of workmen drilling a fourth bore of the Caldecott Tunnel.
Work began Sunday afternoon on a fifth bore hole into another section of the mine, in the hope that the miners may have sought refuge there.
Mr. Murray's new assertions came on a day when a fifth bore hole dug into the mine with the hope of revealing signs of life hit mostly rubble and a small open space, an official with the mine said late Wednesday.
A second bore hole and pipe are drilled parallel to the first but 15 feet closer to the surface.
The turnpike commission announced plans to build a second bore at the Allegheny Mountain Tunnel and a four-lane bypass of the Laurel Hill Tunnel in 1960.
By the 1930s, capacity was becoming inadequate, and consequently a second bore opened in 1967, handling southbound traffic while the earlier 19th century tunnel handled northbound.
Or a third bear scurrying down a drainage canal after a wildlife officer chased him out of a tree.
