BTW, one of the best, least-utilized guard zone mining areas (for ore elementals) in the Trammel ruleset is Umbra, as you can mine the rim of the moat, as well as the mountain face in town, and are never more than a few steps from a guard zone at the times you aren't actually inside the zone. That way, you fight the elementals from the Garg picks, then if things go badly, you can take a couple steps and have it guard-whacked, if it's too dangerous (you don't get ore, but you get your life). And, to an extent, it's probably good for the same reasons on SP, for combatting PKs. If you see them coming (or they attack), step away into the guard zone.
As for smelting...
If you smelt high-end ores in smaller piles, you'll get more ore back, over time.
Sure, if you succeed the first time on a pile of 100 Val, you get 200 ingots, but if you fail once, it's 100, twice 50, 3 times 25.
The ingot return is NOT a function - it is discontinuous (you can't get any number from 51%-99% back on a failure). So attempts by people to claim that there is no difference in small or large smelts, fail because their assertion is based on a false notion of how the math works. What DOES happen, though, is that smaller batches will get you returns closer to your expected mean, instead of being guaranteed to not reach the mean if you fail the first smelt on a single file, because you automatically drop to 50% return from the original amount at best.
If Smelting worked like cooking stacked raw fish steaks (each item is considered a separate check for the skill, for gains and for each item, so at low levels you almost never get the same amount of cooked steaks back from piles of equal amounts), then there would be no difference in the long run, for smelting. but, not with the current smelting system.
From the mining FAQ:
In the end the OVERALL gain rate from Valorite ore to ingots will be about 64.5% (at GM Mining).
52%*2+(48%*52%*1) = average ingot payout per large ore, smelted individually.
1.04 + 0.2496 = 1.2896 ingots.
In other words smelting 1000 valorite ore pieces individually will on average give some 1290 valorite ingots (doing the same for the equivalent 2000 small ore would only return 1040 ingots on average). The numbers change slightly as your piles get larger.
4 ore example:
(52%*8)+(48%*52%*4)+(48%*48%*52%*2)+(48%*48*48%*52 *1) = average payout for 4 ore smelting.
4.16+0.9984+0.239616+0.05750784 = 5.45552384, or an average of 1.36388096 ingots per ore.
HOWEVER, this is misleading to an extent. If one fails 4 times in a row, smelting 4 ore, 1 at a time, one loses 2 ore completely, but still has a chance of getting 1-4 ingots from the remaining two ore. If one fails 4 times in a row on a pile of 4 ore, smelted as a unit, one is left with ZERO ingots. Given that the UO Random number generator is excessively prone to streaks (granted, ones that can be either to your detriment or benefit), it all comes down to a form of loss prevention decision.
Either you can smelt high-end ore in smaller numbers, sacrificing the chance for maximum gain, to get something closer to the expected average ingots returned,
OR....
You can go all at once, hoping for a 100% return, but risking an automatic loss of 50% on one failure, 75% on 2 failures, 87.5% on 3 failures, etc.
One should EXPECT the number of successes and failures to balance out in the end, but one has to consider one usually does not have the same number of ore, each smelt. Failing once on a 1000 ore smelt, statistically, is the still the same as failing on a 1 ore smelt, despite the fact one has a loss of 1000 ingots potential, and the other, only 1. Choosing a set amount to smelt at one time, you can limit your short-term losses, by forcing your results to more closely approach the mean (theoretical average).
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Real in-game Example:
It is near certain that one will get over 1000 ingots from smelting 1000 Valorite ore, in groups of 4. In fact, the average amount one will get back is about 1364 (1363.88).
However, smelting the pile as a whole, gives you a 52% chance of getting 2000 ingots, BUT a 48% chance of getting 1000 or less! In fact, there is about an 11% chance that you will get 250 ingots or less (a little under the odds of flipping 3 heads in a row on a coin, which is 12.5%).
If one is needing to fill a 10-count Exceptional Valorite Plate LBOD for a Verite Hammer, one will need at least 1000 ingots. Which is the method most likely to give you the ingots you need, without having to go back and mine more?