The two companies have entered a binding heads of agreement for an earn-in and joint venture which could see HPX gain up to 75% of the past-producing, silver-gold-copper-lead-zinc project.
Friedland concurrently agreed to a C$2 million private placement financing into Brixton, priced at 23.5c per unit.
Brixton said it would use those funds to cancel 1.5% of the 3% net smelter returns royalty on Hog Heaven, held by Pan American Silver.
According to the agreement, expected to be finalised by January 31, HPX will pay US$4.5 million in cash and spend $15 million on exploration to earn an initial 51%.
HPX would control and direct all exploration activities and principal geologist Graham Boyd said the company saw "high potential" for further discovery at Hog Heaven.
"We believe that the past producing Flathead mine, where Anaconda Copper historically produced high-grade, direct-shipping silver-gold ore, is just one part of a much larger precious metals and copper system," he said.
Brixton chairman and CEO Gary Thompson said the company was excited to partner with the leading exploration and mine development group.
"This $44.5 million earn-in agreement highlights the high quality and significant potential of the Hog Heaven project and is an endorsement of the work the Brixton team has been doing," he said.
Brixton has reported high-grade drilling results from Hog Heaven this year and had been planning to update the project's historical resource by 2021.
The explorer also has the Thorn gold-copper-silver and Atlin Goldfields projects in British Columbia and the Langis-Hudson Bay silver-cobalt project in Ontario.
Brixton had C$5 million in cash this month, according to an October presentation, having raised $5.5 million in August at 25c per unit.
It counted Eric Sprott as a major shareholder and Rob McEwen, US Global, Pan American Silver and Hecla Mining were also on the register.
Brixton shares (TSXV: BBB), which have ranged from 8-57c over the past year, closed up 14.5% to 35.5c, valuing it at $61.5 million (US$46.6 million).