A by-product of mining holds the key to stripping out “gigatonnes” of carbon dioxide from the atmosphere, according to a Canadian start-up that has raised more than $12m and has been testing its technology with BHP in Western Australia.

Arca has entered a new partnership with Wyloo after testing its climate tech at BHP’s Mount Keith mine. It has also raised $US8m ($12.65m) from Side Stage Ventures and Saniel Ventures to accelerate its development.

NBN Co boss Ellie Sweeney has dodged questions about a push to slash up to $2.5m off her annual salary to make the government-owned telco more affordable and better reflect the cost of living crisis.

NBN Co also says it is exploring launching a low Earth orbit satellite service like Elon Musk’s Starlink after a cratering of sales of its decade-old Sky Muster offering.