Opening day for the Baltimore Metro to Johns Hopkins Hospital will probably be delayed from June 1994 to the spring of 1995 because of problems with tunneling machinery and the layer of gasoline-soaked sand that workers struck last year, the chief of the Mass Transit Administration said yesterday.
Ronald J. Hartman, MTA administrator, also said the cost of the delay, new digging machinery, safety modifications to old machinery and the installation of explosion-proof electronic equipment is expected to reach $20 million.
But he added that the $20 million would not increase the original $321 million budget for the 2-year-old construction effort because that budget includes a $53 million "cushion" to pay for just such unforeseen problems. Eighty-five percent of the $321 million is federal money.
The cushion was added, he said, because the MTA discovered the fickle nature of underground work during construction of the first section of the Metro. That section opened a year late, in November 1983, and cost $10 million more than expected
because of problems constructing the Charles Center station.
"Underground tunneling is just fraught with uncertainties," said Mr. Hartman, explaining why the contract included so much money for contingencies and other changes. "That was our experience on the tunneling for the first sections of the subway. All the drawings in the world, all the borings in the world -- they are useful, but there's just no substitute for going down there and digging."
Delegate Timothy F. Maloney, D-Prince George's, chairman of the House of Delegates subcommittee that oversees the state's transportation budget, said he was concerned by the problems.
"A nine-month delay is a fairly significant amount of time no matter how you slice it," he said. He noted that the state's share of the higher cost is only $3 million. But he also said Maryland has extensive transportation needs and is having trouble finding ZTC the money to pay for them.
Last fall, tunnel workers, called miners, began smelling gasoline in the two tubes being dug from Hopkins to Charles Center, the current terminus of Baltimore's single subway line.
Then in November, sandy soil at the face of one tunnel "spilled" into tunnel-digging machinery, creating a void that migrated toward the surface, undermined water mains and eventually created a 12-foot-deep sinkhole in the eastbound lanes of Orleans Street at Broadway. (The completed section of the 22-foot-diameter tunnel, which is lined with concrete sleeves, was not damaged and never threatened to cave in.)
The damage from the spill was repaired and work resumed on Dec. 3, but was interrupted after the gasoline fumes grew thicker and miners began complaining about headaches and nausea.
Workers were outfitted with filtered- and forced-air face masks, but concern about the potential for fires and the health of miners caused the MTA and its tunneling contractor, Kiewit-Shea A.J.V., to halt work Dec. 18.
Since December, Kiewit-Shea has installed ventilation pipes 4 feet in diameter, redesigned its tunneling apparatus to prevent future spills and ordered explosion-proof electrical equipment in the Hopkins tunnels.
Work is expected to resume in the two Hopkins tunnels in September, MTA officials said. Meanwhile, Mr. Hartman said he decided to reduce some of the delays by beginning a separate tunneling operation from the Shot Tower station toward Charles Center.
Mr. Hartman said the agency was still looking at ways to speed up the project.