I did a quick check on the internet and found that the average broadsword would weigh around 2kgs, more or less. The average iron ore contains around 65% iron/volume, meaning that a good round figure would be that it takes around 3Kg worth of iron ore to actually make the sword in terms of materials. That, depending on the richness of the vein of iron ore you've found in your mine, the fatigue and/or stamina of your dwarf, transport time for both the dwarf and the resultant ore from and to the surface, sounds like a couple of hours work under ideal conditions.
But, that's not your real resource problem. Your real resource problem is coal. You're going to need around 10Kg for just a few hours of working with the metal after it's smelted, and a LOT more than that to actually smelt the ore in the first place. So, your dwarf is going to have to work in at least two mines to make your sword as the iron ore provides the metal, but the coal is needed for the energy. So, if you have a rich vein of anthracite coal around, add a couple of days of effort to the materials gathering. If you don't have ready access to the right coal around you, this could blow out to a couple of weeks or worse.
But, that's not your real problem. Your real problem is the skills and time required to fashion the sword in the first place. Just looking at what was required to make a Katana in feudal Japan you can see that the skill required to forge and create such a sword is no small contribution to the process, and there are also steps where the metal must be folded many times to get the metal in a ready state to become a strong yet flexible sword.
Bottom line is that your metal for your sword isn't your bottleneck; your energy supply (coal) will take more effort simply because you'll need more of it, and even with your ideal skillset required to forge the magic weaponry it's going to take more time to do that then find the raw materials.
Remember, this is not the industrial revolution yet and your artisans aren't competing with factories that can churn out hundreds of ready-made magical daggers all of the same quality and type because they have replicable manufacturing figured out. Each of your magical items will be hand made and in all likelihood, your dwarf is going to be sitting around for around half the year unless he's supplying more than one artisan of magical weapons.