HCH potential Water business, page-49

A high level speculative overview of a raw seawater supply system for Hot Chilli;

• Distance from Coast to Productora from the first map ~20km
• Elevation from Coast to Productora is approximately 740m in elevation
• Flowrate for 150,000tpa is around 1000L/sec

Based on this at a high level;

• Would require a pipeline approximately 1m in diameter. Possibly polyethylene or mild steel cement lined. Bit out of touch with supply and installation rates of this diameter pipe but it would likely to be $1000/meter laid but it would depend on whether its trenched or laid above ground. I recall in my visit to Atacama region there were many large poly pipes traversing landscape above ground.
• It it was polyethylene then the vertical lift to get this volume of water to 740m is likely to require at least 2-3 tanks and lift stations. Most poly pipes have maximum rating of PN20-PN25 or 200meters of pressure so lifting 740m will require about 3 pump stations with breaker/feed tanks to get to the mine site.

For raw seawater i suspect polyethylene would be the best material due to corrosivity of the water. Large lined and covered raw water basins or very large tanks will be needed. I suspect lined basins maybe the most cost effective and durable.

Pipeline Costs @ 20km of 1m diameter pipe x $1000/m = $20m + contingency = $25m
Lined Basins 3 @ $750k each (will depend on volume and local conditions = $2.25m
Booster pump stations @$1m each = $3m
Raw Water Storage @ Productora - depends on size but maybe $3-5m for a decent lined and possibly covered earthen basin. Much more expensive for tanks.
Seawater intake structures - this is quite unknown and will depend on the marine permits and requirements This can be quite expensive!

Above is speculative since there is many factors that can influence costs including permits, topography etc but the CAPEX for raw water supply is a far more economic proposition than desalinated water. Opinion only - DYOR