Gob
Gob turns up in 2 fields: mining, shop slang. Here is what it means to the people in each one.
Gob in mining
The mined-out area of a coal mine or the compacted waste rock filling it.
The mined-out area of an underground coal mine, or the compacted waste rock and refuse used to backfill these empty spaces. It serves as a repository for unwanted material and allows the overlying strata to settle in a controlled manner after the coal is extracted.
"We need to seal off that old gob before the spontaneous combustion risk gets any higher."
Gob in shop slang
A messy, imprecise lump of grease, sealant or weld metal.
A thick, shapeless mass of viscous material applied without care or precision. Technicians encounter gobs when previous workers have over-applied silicone sealant, grease, or flux in a frantic attempt to stop a leak or force a fit. It indicates sloppy workmanship and usually requires extensive scraping or grinding to clean up before a proper repair can be made.
"The last guy just put a massive gob of RTV on the water pump gasket instead of cleaning the mating surface."