Another eight-hour search has failed to find a clue in the disappearance of a Tamaqua man.

On Sunday, a high-tech robot was lowered 400 feet to the bottom of a mine shaft and came up empty in the search for Jesse Farber, 29."It stopped. It hit a ledge or a room," said Norma Jean Fritz of Jim Thorpe, Farber's mother.Farber went missing without a trace on Aug. 11, presumably on Sharp Mountain in Tamaqua."They scanned the whole area. They found three out of four tires that broke from a camera that was used last week," Fritz said.Crews also dropped pingpong balls and other small balls into the hole as part of the exploration process."The balls disappeared," Fritz said."But there's no evidence of anyone being down there and no evidence on the way down, too."There is speculation that Farber could've stumbled into one of many open mine holes.Family members and searchers hoped the robot, built in Canada, would provide information on the whereabouts of the father of two, now missing for 34 days. At this point it appears searchers will rule out the mine void and refocus.Joint effortThe equipment arrived in Walker Township Sunday morning and some 25 volunteers from regional search and rescue teams immediately went to work.Crews from Northeast Search and Rescue coordinated the search using the special rescue camera donated by the Canadian company Inuktun InCommand Robotics. The operation and deployment of advanced strategies was kept under wraps in order to avoid unnecessary distraction.The air shaft initially was believed to be 1,100 feet deep and searchers were counting on the robot to overcome the sheer depth which no camera had been able to fully penetrate.Coming up empty has once again proven to be frustrating for all parties."We want closure for your family," said one volunteer to a heartsick Pat Ferryman, Farber's grandfather.Ferryman said the family has been enduring endless emotional pain."This is driving us crazy, the not knowing," said Ferryman.Ferryman's wife, Rae, known as "Sweetie," has been distraught over her missing grandson, something she's had to cope with for the past five weeks."She's worked up," Ferryman said.Top of mountainThe operation was headquartered at a makeshift base camp set up near Rabbit Run Reservoir in New England Valley.From that point, ATVs were used to shuttle searchers up the steep slopes of Sharp Mountain, which spans Walker Township and Tamaqua.According to volunteer Dave Slane of Minersville Fire and Rescue, the air shaft of interest is located at the top of the mountain.It is the same air shaft where, nearly a month ago, officials from the state Department of Environmental Protection lowered a camera some 175 to 200 feet before a lens broke.Slane said the deep hole is typical of many such openings found throughout the anthracite coal fields."We have them all over the place in Minersville, too," he said.NESAR announced last week that a robot would be deployed. First, however, the group had to raise $1,300 to cover shipping costs due to the weight of heavy cases, 1,600 feet of cable, monitors and the robot. The equipment required a 600-pound pallet.NESAR has made it clear that the mission was exploratory in nature and that nobody really knew for sure if Farber was down there.Fritz takes satisfaction in being able to rule out the deep shaft."I knew my son was never down there," she said.NESAR was joined by crews from Carbon County EMA and its mobile command, Monroe Safety Center and Minersville Fire and Rescue.Other parties and entities that have attempted to locate Farber include Pennsylvania State Police, K-9 units, a military chopper from the Pennsylvania National Guard, Pennsylvania Wilderness Search and Rescue, local fire companies, ATV hobbyists and others.Most of the searches were conducted in oppressive heat and humidity, with professionals and volunteers scouring ridges and valleys between Tamaqua and Walker Township.The mystery has provided plenty of speculation, but little in terms of factual information.Anyone with information is asked to call Fritz at 570-449-3985, or Tamaqua police at 570-668-5000.