So if you actually place the statue it's worth a lot more. I started with stone statues when I was first figuring out the game and what all the stuff does so my next try I made a copper statue and I noticed when placed the value is between 700 and 5000 based on quality. My next try I found a bunch of silver which was between 1000 and 15... Game actually says 15... and it's better for homogeneous statues than mixed ones. Last try I was making Gold statues which when placed are between 2k and 50k when placed. Most of the time I found gold under -70 depth. I was putting them all in my great hall with a few tables and chairs and the food and drink stockpiles, one for each. Stone statues are only worth about 9 to 50 when not placed and 210 when placed. Similar with wood. So at the end I would get my miners to only mine and have everyone else working on hauling or smelting and metalcrafting depending on if they had natural talent for metal crafting or not and after I made 6 crates 2 for coal 2 for ore and 2 for bars i just hauled and smelted the rest of the time.
So basically the process is you have to make 96 planks and 40 stone blocks, a carpenter for the crates and 4 tables and chairs which is deconstructed when done, 2 smelters that I raised the priority in the overview tab, a furnace, a copper metalworker, top priority, that I usually find the ore for on the way down along with some other trash tin or malachite that I use to make the first 2 crappy statues with to warm up my crafter, then the rest of the time just try to get to gold or silver. Don't bother with a dorm or foraging they usually have enough to last them if you place a stockpile for them to find the stuff. At the workshops if they don't have the materials to make something they will start on the next thing on the list but they will try to make the thing on the top first if they have all the ingredients so I keep my smelters going non stop by having them prioritize gold(repeat) then silver(repeat) then any metal(repeat) and the same at the metalcrafter. The only thing about gold is the ore is some 200 steps away so on the last 2 days I have 3 guys smelting, making coal or making statues and NO hauling and everyone else is bringing them the materials and placing the statues... And that's a lot of text but that's what I did.
Also I didn't use the stair trick to find ore I looked for holes and was just annoyed by them not being able to place stairs in a nice straight line or having my miners get stuck and unable to get back up.