HRR - Updated NPV calculation, page-39

Indeed, but let me expand on your numbers above. Looking at their yearly production estimate and recent base metal prices (USD) 12/04/2018.
Zn 70,000 dMt @ $3,238 = $226,6606,000
Cu 30,000 dMt @ $6,887 = $206,610,000
Pb 25,000 dMt @ $2,500 = $60,000,000

These guys are looking at an NPAT of $493,270,000 once in production!
This doesn't even include the precious metals by-product which the company does not forecast.

Cons:
- Heron/Woodlawn is a junior miner with a large possibility of production delays.
- Zinc has a low price trend risk during tepid economic growth
- Historically Zinc can be priced well below the cost of production for years at a time
- Supply side story and not demand

Pros:
Heron is...
- Funded up to production Q1 2019
- High quality sulphide deposit resource base
- Existing transport infrastructure and power, strong community support
- Brand new state of the art processing plant and equipment
- 9 Year mine life (9.24 million tons reserve starter case)
- Plant has capacity to produce an average 1.25 million tonnes of tailings and underground ore per year that means 150,000 tonnes of lead copper and zinc equivalent annually
- Most of Chinas Zinc production has shut down
- Tight zinc market
- Zinc battery technology will boost demand
- Dwindling world supply (Conjecture - LME Zinc/Copper showing up on its door recently due to higher prices)

But I'm not complaining as I'm planning to buy some more....