Phelan would encourage equal pay for equal work and non-discriminatory policies on hiring. He would further remind Jamran that due to her Imperial Charter, her decisions reflect on the Prince, who in general has taken a even handed and non-discriminatory approach on hiring, and has in fact raised members of so-called "lesser" races to the ranks of Imperial Knighthood, with no caveats or treating like they are lesser than others.
As to actual values. Going off DnD rules per the
d20SRD for Goods and Services, a laborer cost 1 silver per day (a tenth of a GP), and a mason and other skilled laborers cost 3 silver per day.
Now, as Dasaria and NWN2 don't have a proper DnD breakdown, I'd actually consider those to be 1 GP and 3 GP per day.
Assuming Jamran hires 100 laborers, 10% of whom are skilled masons and engineers who lead teams, that's 90 @ 1 GP/D, and 10 @ 3 GP/D, giving a daily labor cost of 120 GP. Assuming a 5 day work week, that makes it 600 GP week in labor. These numbers are obviously subject to change based on the size of the workforce.
As to material costs, let's break it down:
Mules for hauling and working. Assume you want 10 mules, plus gear for them. 10 mules cost 80 GP and their saddling is 5 GP per, so 50 GP total, giving a total plus you have daily housing for them, which is 5 SP/day, rounding up to 1 GP/day, housing for pack animals would be 7 GP a week.
So far we have:
Initial Outlays: 130 GP
Weekly Costs: 607 GP
Tools for laborers is a little harder to figure. You likely don't need a full set of Artesian tools for EVERY laborer, but we can break down some of the costs:
Sledgehammer: 1 GP per
Miner's Pick: 3 GP per
Hammer: .5 GP per
Rope (Hemp): 1 GP per 50 ft.
Shovel: 2 GP per
Artisan's Tools: 5 GP per, or 55 per if you want masterwork
Now, assuming you'd want about 50 of each tool, 10 of the artisan's toolkits (non-masterwork) for the skilled masons and such 1000 ft of rope at least) that gives us the following cost in tools: 365 GP.
Initial Outlays: 495 GP
Weekly Costs: 607 GP
That said, there's a lot of other equipment needed, chests, lanterns, ladders, etc, etc. There's costs for single items in that page I linked, but that page really only is reflective of the cost of single items sold to an adventurer. It does not reflect the economy of scale that making massive orders would allow Jamran to cut some costs, but it also doesn't give costs for things like nails and raw wood.
If I had to ballpark, I would set aside 2000 to 3000 GP for building materials and initial outlays, and a similar amount to account for weekly costs.
All that said, that's working off of NORMAL DnD rules where 1 GP is actually a whole lot of money. 1 GP in NWN2 actually seems to be closer to 1 Silver Piece in many respects. 1 SP is 1/10th of a GP in DnD, so if we apply that conversion to these prices... we're looking at ~25,000 in initial costs, and ~25,000 in weekly costs. Assuming tools and other things would need replacing periodically, you'd probably need to set aside 10,000 GP/month for new materials and tools.
So monthly costs (assuming 4 weeks a month) would be: 110,000 GP, and a yearly operating cost of 1,420,000 GP. For a nice even number, I'd look at trying to raise 2 Million GP as the initial investment for gearing up and initial operations, as that gives a good amount of leeway to accommodate unknown costs, such as hiring adventurers to clear out dangerous areas.
TL:DR:
2,000,000 GP seems like a reasonable initial investment goal to me, based on way to much delving into DnD rules. -.-
These projections should be for the foreseeable future beyond one year after the mine officially opens