Credit for majority of this goes to www.mooglebox.com
, Jet Chan and Aviha Chai from Balmung, and Aleczan Knighthill from Excalibur, as they went through setting everything up, finding all of this information, making sure it's all accurate, things like that.
Information listed here is from personal experience, and from http://mooglebox.com/gathering/index.php
Copied directly from MB:
There are four possible lengths of the starting remainder bar, and each item consistently uses the same one. So, if you're at Iron Lake, and you start mining, and the remainder bar is at placement B, then you know that you're about to dig up some cobalt ore.
The second consistent input for each item is the strike zone. Logging uses five zones, and mining and fishing use four (there are other theories, but if you follow these you'll be very solid). The images show good places to strike to hit each zone. Cobalt ore's strike zone is 4. So, if you're mining at Iron Lake, and the remainder bar is at placement B, then you know that you merely need to strike at zone 4 to dig up your cobalt ore.
Note: In order for the strike zone to be consistent, you must be high enough level and have adequate amounts in the appropriate stat (Botany STR, Mining VIT, Fishing DEX). When you don't meet these requirements, the item may be placed into a random zone.
Using the information from MB and everything from the items gathered by area pages also located in the wiki, you should be able to consistently find what it is you're looking for.