Sounds like a great adventure, Todd. Best of luck in your search. You've asked some great questions. I hope I can give you some reasonable answers! I was fortunate to have recovered a buried cache for a family a few years back. The circumstances surrounding your situation is somewhat similar in that the family who contacted me felt confident there was silver buried there...... they just didn't have any idea where it could be.
In respect to your questions....
If you were conducting the search for mason jars buried for as long as eighty years what coil would you be using for the greatest depth?
When the "old timers" buried money, as you said, it wasn't to hide it "long term", it was buried for safe keeping, out of the hands of the banks. Based on my recovery (using the X-TERRA 70 and 6-inch DD coil), I'd suggest it will be deep enough that it is well out of sight, but not so deep they couldn't access it in a short period of time. After all, they were likely making "depostis and withdrawals" on a regular basis. The buckets I found were all less than a foot deep. And even though yours may have been buried for 80 years, if it hasn't been tampered with, I wouldn't expect it to have "moved" a few inches, at the most. Of course that all depends on how much dirtwork has been done around the old farmsite.
With a buried mason jar am I right to assume if the jar is buried right side up I would be reading the lid not the silver?
The jar was likely buried right side up, to keep out the moisture. But honestly, it won't likely matter if you read the lid or the coins. I have a found dozens of mason jar lids (or zinc jar lids) that gave a TID similar to a large coin. So although I wouldn't use much discrimination, if the area is cluttered with pieced of old farm implements (iron), I'd likely dig everything with a CO reading of 26 and higher. If you are sceptical as to whether or not the TID of 26 will be "enough", dig them all. Once you get tired of pulling up "trash", mark those targets having a lower TID so you can come back to them if you need to.
Because of the size of a mason jar lid and time spent buried how deep would you expect the detector to go? In moderate soil conditions.
As I mentioned, the cache that I found was less than a foot deep. I was using the 6-inch DD because I was working in and around buildings. If you are using a larger coil, I would think you should be able to hit a quart sized jar of silver at 16 inches or more.
I know where the cloths line, outhouse, ice house, well, parking, barns, silos and garden was located throughout the last eighty years, we're would you start your search?
"Back in the day", folks buried their money in a location where they could keep an eye on it from the house. A good place to start might be around one or the out-buildings that could be viewed from their bedroom window. Even though it was buried, that doesn't mean gma didn't want to "keep an eye on it". If they had a chicken house, you might check in and around there. I remember my grandma telling me that is where she kept her cash. She figured if anyone came around looking for it, those chickens would let her know. If there was a fence around the garden area, check out under the old posts. (post hole banks) Folks could simply lift up the post, drop the cash in the jar, and put the post back in the hole without leaving a trace. If the buildings are still standing, check around the perimeter of each one, inside and outside. Check under the floor area of the ice house. Check out the area behind the outhouse. People don't "snoop" around those places, and your gma might have had that in mind. Put yourself in gma's shoes for a few minutes...... stand where she may have stood, lookking out the window. And start hunting those areas that are hidden from the main road, not far from the house, and within her range of vision. If you don't find it right off the bat, expand your perspective and keep on looking.
The property will be sold and I will get about three days vacation to find what I can this fall because I live in Nevada, so any advice or suggestions would be appreciated.
Three days doesn't sound like a long time. But let me give you some encouragement..... I found that cache I was looking for in less than 3 hours. You can plan the hunt in your mind over and over again. But sometimes, it is better to be lucky than good. And finally.....if you are heading up toward the NW corner of MO, I ain't far away. If you need some help, give me a shout. HH Randy
all I have is time. HH Randy