ReTe Craft Questions

I just finished reading Covenants with an eye towards our current Saga, and I was left with some nagging questions. I was hoping in this thread to solicit some advice from the forums on the topic of Rego Terram craft spells as they might be used to extend/create natural caverns or to mine.

Basically, I expect the players to, at some point, decide to try to use ReTe spells to either create/expand a mine or to expand some existing caverns. Now for a mundane miner this is back breaking work, fraught with considerable danger in this time period, requiring timber and luck (or rare engineering knowledge) to shore up tunnels, avoid aquifers and flooding, trapped gases and oxygen issues and the like. The crux of my questions are basically what of these issues apply to ReTe effects.

So, let's say a magus invents an ReTe spell, The Magus' Major Miner General spell for all mining purposes. The spell pushes back stone and earth, compacting it, allowing the magus to shape passageways through natural earth. Base Effect 2 (slightly unnatural or as a craftsman), +1 to include stone, +1 for "subtlety" (making passageways and rooms), +1 Touch, +1 Part, +1 Size. Level 15.

Assuming that spell is even valid 8), he should then be required to make a Finesse test against an ease factor +3 higher then the comparable craft. If a miner were going to attempt to do this, I would probably give him a very high ease factor (I'm inclined to say 12, possibly with bonuses based on materials used, precautions reducing botch dice of which there would be many extra), as mining in this period was quite hard (and in fact, as we think of it, probably didn't exist). It seems unreasonable, however, to impose the same difficulties on the magic. First there was a passage in Covenants saying that one casting of a spell amounted to about 1 days work of a single craftsman. That would seem to dramatically reduce the roughly 10 cubic paces of effect of the spell (but perhaps that's covered by the size modifier already). At the same time, I can not seem to decide whether a magically created passageway would require shoring beams and support. On the one hand it seems like it absolutely should as the mass is still present, only compacted, increasing the likelihood of a cave-in. Afterall, natural caves themselves do cave in even absent human intervention. On the other hand, however, there is an argument for the non-disruptive nature or manner of the rego magic not breaking the bonds of the stone with itself or the sediment, therein mitigating substantially the risks normally incurred by much more intrusive mining tactics, particularly, it would seem, if shaping through a vein of "solid" igneous rock for instance. If I were to buy that argument, I suppose I could just reduce the botch dice. If support beams were added as the work was done, that would seem to add further mitigation. What ease and risk factors would you impose?

As a secondary advice issue, let's say the above ReTe spells are being used inside a magical cavern. Now, I know many people are going to suggest that it all depends on my saga and why the caverns are magical, etc. My problem is that I lack a sufficient Ars vision to really have a feel for how working the caverns would effect the aura (or the regios) in the cavern complex. A passageway you only see if you've passed it four times, for instance, might not show up if the passageway it is suppose to appear in is expanded into a full cavern (or maybe it still does, only now it's in the middle of a giant room, making it much more obvious). Maybe you're already in the Regio when you see the side passage, I could play with the definition to avoid the question, but for pre-existing conditions that would seem problematic. Also, what happens to the Aura itself? Has anyone run magical caves that have gotten modified or expanded in game and how did you arbitrate the impacts of those expansions?

Personally, I don't feel that the task of mining out caverns falls under the auspices of craft magic. It is not "building" something, per se, it is removing stuff. Turning a pile of wood into beams used to brace caverns... that's craft magic.

The obvious choice for what they're trying to do is PeTe, of course. I've seen interesting Mu effects that make me think MuTe could conceivably do the trick. And I'm sure there are probably even helpful ReTe effects that could be used to break away a piece of rock and move it out of the cavern. I could even see the effect you describe working in dirt, but less so stone, which is usually fairly compact to start with.

The crux, to me, is that what the spell is trying to do (compact stone to make a hole) is not what the miners do (as far as I understand); miners break stone off and carry it out, they don't just push rock into other rock to make a hole. If the magi want to make a ReTe spell that causes a rock face to break into a bunch of pieces as though a pick had been taken to it, I could see that as craft magic, but they'd still have to deal with removal of said rocks.

As ndkid has suggested, I'd use MuTe with a Pe AND a Re requisite: perdo to get rid of excess material, Muto to do most of the 'work' by changing the nature of the stone to make it soft, rego to move and then to compact that softened rock into the shape you want, then the muto effect expires leaving very solid rock behind. Quite a high finesse roll to achieve structurally sound results (buttresses, pillars in the right places depending on the type of rock, etc).

You could use multiple seperate spells instead, if the magi can't achieve the casting/lab total needed. Probably level 30, although that's just a guesstimate based on your original spell.

If the magus doing the casting has a relevant craft skill (mining or architecture or proper geology etc), then I could go with an easier finesse roll IF he/she made the craft skill roll. It would even be possible to hire a skilled miner to make that roll and give instructions - the finesse roll would simply be to see if the magus were able to follow those instructions accurately.

As far as real mining was concerned, there are/were some very extensive mines around in the real world, but only in certain locations (eg there are the absolutely massive copper mines within the Great Ormes Head by Llandudno in north Wales which were made during the bronze age; there are iron mines around that aren't just open-cast in several places). Personally, I'd look to hire a magical dwarf if I wanted a real mining expert in Mythic Europe (you can't trust faerie ones...).

You just have to decide if you want this to be a story, or just a 'make the spell and use it to make what you want' sort of event.

"compacting it", that would be SERIOUS work... If you really want to do it that way, i suggest you start with Base 3 as the compacting part is the highest base effect, probably add an extra magnitude for how VERY unnatural it is, and add +1 magnitude for doing the shaping effect as well. Might even be worthy of an extra magnitude still.
And your spell is certainly NOT craft magic, as it does something humans cannot.

Rather than "subtlety" i would say its complexity.

However, if i wanted to go drilling through a mountain, the most easily, i would probably use MuTe, either to make it into water(with Aq requisite) or to make it very soft, ~jellylike and simply remove it or for water, have it run away by itself.

Gilarius, do note that 1, magi can find things to mine FAR more easily than mundanes can and even more importantly 2, magi can easily mine metals from places where mundane miners would struggle to get anything useful from.
It´s far more common that a place isnt commercially worth the effort to mine, rather than not having anything worth mining for.

Que? A bit of a non-sequitur, surely? ("Don't call me Shirley")

I said that there were real mines; and that if I wanted an expert, I'd hire a magical dwarf. What does that have to do with what you wrote? The OP wasn't asking about finding anything to mine - that would be InTe, obviously.

Please explain, I'm confused :wink:


A lot of crafts mostly amount to removing material: Stone carving, whittling, ice sculpture. That doesn't mean that craft magic rules shouldn't apply to them. For me that also doesn't mean perdo can do the job all by itself. Rego is all about control. Shaping a slab of granite into a statue is an exercise in control. Perdo destroys things, even parts of things, but I don't let it have skilled craftsman control all by itself even with a finesse roll. Perdo wants to ruin and destroy not make straight lines and regular curves.

I work it out this way.

A ReTe spell to carve stone instantly transforms the stone into a finished shape with a pile of rubble around it. Exactly what you'd get if a craftsman had worked on it but in far less time. Of course the is quality determined by your finesse roll. Adding a Perdo requisite would allow the spell to also dispose of the rubble.

A PeTe spell with a Target Part would allow you to carve out rough shapes but coming close craftsman quality would for me require a Rego requisite. Even with these I would never allow Pe(Re)Te to be as flexible as craft magic is.

I think that the point was just that a magus with Intellego Terram and some given suite of Mu/Pe/Re Terram effects is effectively an expert (or even better than an expert) at mining.

As for the original question, I think that it should be entirely possible to effectively mine with a combination of some/one/or all of Mu/Pe/Re Terram effects. Precisely what combination of Techniques and effects is best/required is more to do with what the magus happens to be good at and the precise context of the proposed mine.

No, i was responding primarily to your "there are/were some very extensive mines around in the real world, but only in certain locations" statement. While perfectly correct, the abilities of magi invalidates it.

And as RL already noted, the other half was essentially, who needs a dwarf when you can come up with some rather amazing intellego-spells?

Another advantage for magi using spells for mining, if they do a +1 magnitude to destroy stone(or similar), any and all metal and gemstone parts of the original stone is left in the open. Moving from metal ore to separate metal can take a lot of work, so a simple spell for mining can double as doing that part of the work as well.

There is a thread somewhere that discussed the question of whether one could use Rego to "create" a better hole in the ground, a mine, or whether it was only Perdo. Iirc, it did not reach a consensus on the issue.

Ah, I understand now - however, I was thinking of using the expert (dwarven or otherwise) to advise on how to construct the mine so it doesn't collapse, flood or be otherwise unpleasant. InTe is clearly superior to mundane knowledge to decide where to dig the mine (although a really magical dwarf might be even better, depending on the saga and SG), but I wouldn't allow InTe to give the magus expertise in mine engineering (it could give a bonus if the magus knew exactly where cracks and fissures and water levels were).

By the way, how do the abilities of magi invalidate a statement made about mines in the real world? (I stated that to show that it is a fallacy to believe that there were no extensive mines around during the 1200s, which was mentioned in Shin's original post.)

Gemstones and gold/silver should be left behind, but would ores? Technically, ores are not actual metals (being compounds) and if you allowed the non-metal parts of ores to be destroyed, leaving the metal bits behind, you'd be left with much more Titanium and Aluminium rather than Iron...what other metals are very abundant?

I think that I'd allow a one-magnitude higher spell that was specifically designed to leave iron behind when iron ore is present do exactly that, but to get a generic 'all metals left' spell would have to be much higher level - or maybe need Rego and Intellego requisites to identify the correct ores and only destroy the relevant parts.


It's perfectly ok to use ReTe "craft magic" without any requisites to dig tunnels or rooms into the earth. You do not need Perdo, unless you want to destroy the escavated material (that's probably best accomplished by a separate, spontaneous PeTe spell) -- if you do not use Perdo, the excavated material will just be neatly piled up outside. You certainly do not need Muto, just like you do not need Ignem to make bread out of flour with ReHe. In fact, if you assume that the effect is controlled by the Finesse of the caster, the +1 "complexity* modifier is not needed unless you want to do something quite a bit more elaborate.

I would have two issues with the OP plans, however. The first is that, unless you are digging through solid rock, tunnels also require some sort of "support" e.g. in the form of wooden logs. If you are digging through clay or the appropriate type of dirt you may be in luck and have the spell use it to form bricks with which to support the tunnel (this should probably, however, bring back the +1 complexity modifier); but you really can't manage it through sand or loose earth -- any tunnel through these will just collapse, no matter how you "compact" it -- unless you use a sustained, unnatural effect. The second issue is that if you are digging through magical rock ... well, anything may happen! For example, the tunnels may shift and turn of their own accord (almost imperceptibly, but with very real effects in a few days).

All of this is true, however see below...

This is what I would use the muto requisite for: to re-shape the rock/dirt so it will be strong enough to support the tunnel/room without needing the extra supports that a mundane version would. Not being a real world expert in mining, unless proven otherwise, I would allow the one-off muto effect to make it strong enough without needing an on-going magical effect.

Now this I like! Yoinked for my own saga, thanks!


I think it is well within the purview ReTe to fuse sediments into construction worthy ceramics (clay -> brick, sand -> quartzite etc.) as craft magic, such crafts were practiced and the concept was well within the medieval conceptual space. It would take extra magnitudes to fold this process into a general mine construction spell.

Would it also be within paradigm to fuse soft chalk into a nice, strong limestone/marble with ReTe? Would it be the same effect or a slightly different spell? Would an Unseen Brickmaker spell give a similar spell bonus to a Chalk Squeezed into Marble spell?

I'm fairly ignorant on the issue, but I thought you could change sandstone into quartzite by heating -- but not sand. Sandstone is not just sand: you need some cement as well. So you can't turn sand into sandstone either. Though you could turn sand into glass.

Ah, but Muto cannot be made "one-off": it must be sustained, limiting the duration to Year (or to Moon without a Ritual) -- barring weird mysteries and "special" magics.

Sorry, I was being unclear. I agree with everything you said. It is the case, however, that when trying to mine, there is no place for the pile of rubble to go. So all you've really done is turn an area of solid rock into an area of really, really well compacted, fits-perfectly-together, rubble.

I further agree with you that you could construct a Re(Pe)Te spell that mines out chambers, and that it isn't quite craft magic. Which goes back to what I was originally trying to say: the result of craft magic is a thing, not an empty space, which is why a completely destructive spell is not craft magic.

I think what I'd need to know before going down this path is how the folks in the Medieval era understood rocks to work. I doubt that in the era of alchemists that it was believed that one could compress one sort of rock into another sort of rock, which would imply that it actually doesn't work that way in AM by RAW. Obviously, different sagas have different preferences as to how AM physics differ from our own. :slight_smile:

All true, but it is also true that I could use muto to turn a statue into mud. That mud wouldn't hold its shape and when the spell wears off, the former statue stays as a puddle of now-solid rock again. For the mining, I'd use the muto effect to make the rock a) easier for the rego effect to move and shape it; and b) to make it so when it 'sets' again it is harder than it was originally, having been squished by the rego effect. Obviously, how much of this extra strength is allowed depends on the SG. You might not allow any extra strength and even I think that some soft dirts still wouldn't hold their shape without proper props and supports, and that would be for the SG to adjudicate.

For what it's worth, I also agree with ndkid that magi couldn't use ReTe to change chalk into marble or any sedimentary rock into its equivalent metamorphic rock - this was unknown even as an idea then, and caused a lot of controversy even in the 19th century I believe. Plus the amount of rego needed would be extortionate (very high pressures = very high magnitude), Ignem (for heat) would be a requisite too. I wouldn't allow my Muto idea above to make this sort of change permanently - it would be an example of how an ongoing muto effect needs an ongoing spell duration, like Ezzelino said.

If you dig a hole, you get a pile of rubble nicely piled next to the hole, not in the hole.
So, first you dig the entrance to your tunnel with a couple of spells -- and you get a pile of rubble next to the entrance, which you dispose of e.g. by carting it off. Then, you dig further, and with each spell you get a pile of rubble in the entrance that does not fill it since the entrance was carved with multiple spells. You dispose of that e.g. by carting it off, ... and so on.

In your opinion and in your saga, of course. Others would disagree, or have other considerations/concerns that might be applicable. 8)

There are several possible "valid" interpretations, depending on what part of the rules one leans towards.

To expand on this explanation - Muto is "unnatural", and Hermetic Magic cannot make an unnatural change permanently (withou vis). Rego changes something from one natural state to another - and that's what some are proposing - but it would be a rather open-ended saga that allows that particular interpretation.

The understanding of the exact relationship and process between sedimentary and metamorphic rocks is quite modern, yes. A mage's view, however, is that one substance can always be transformed into another, but that would indeed be Muto rather than Rego, as it would indeed be "unnatural" to, for instance, turn mere coal into diamonds. :wink:

("Craft magic" might fuse sand into glass, but I can think of no other "craft" that would compact one rock into a (noticeably) denser form.)