RML returns high recovery rates from Antimony at FAST-41 project in the US
Our US gold-antimony-tungsten Investment Resolution Minerals (ASX: RML | OTC: RLMLF) just announced metallurgical testwork from its Antimony Ridge project in Idaho.
(source)
This is the project that recently received FAST-41 designation by the US government.
AND the same project that has historically produced:
- During World War 1: RML’s project produced antimony.
- During World War 2: Antimony was produced again.
- In the 1960’s: There was even more Antimony production.
- And then between the 1950’s & 1980’s: Tungsten.
Today, RML showed that testwork on samples taken from the project returned high recovery rates with “virtually all of the stibnite would be captured in the rougher flotation concentration stage”.
We also noticed RML said it’s plan is to develop a “hydrometallurgy processing hub for antimony, as stibnite, in Idaho”.
So RML is already thinking about how to get the project back into production AND how the rocks can be processed using typically more environmentally friendly hydrometallurgy…
Although we are interested in the antimony, it is the sulphur recovery that is the key number because this shows how much of the stibnite (antimony bearing mineral) is being extracted from the samples.
RML managed to achieve a 99.5% sulphur recovery in rougher flotation indicates nearly complete recovery of the stibnite (antimony sulphide) from the sample.
So the result is yes, that the simple gravity/flotation circuit works, and most of the antimony from the stibnite is being recovered.
RML now has further works underway on this looking to bump up the concentrate grade from ~30% to ~50% antimony, this would be done through further concentration stages.
This complements RML’s antimony trioxide result we covered last month (RML produces antimony trioxide from Fast-41 status project in the US).
This is where RML produced a 99.38% antimony trioxide product using the conventional pyrometallurgical volatilisation process.
So now RML has metallurgy results validating both ends of the antimony processing pathway:
- Upstream: flotation concentrate recovery at 99.5% sulphur recovery / 76% antimony recovery (today)
- Downstream: 99.38% pure antimony trioxide via volatilisation (April)
So the early signs are that a clean, simple, conventional processing flowsheet from rock to refined product can be produced.
Importantly from a project that already has FAST-41 status from the White House.
What is FAST-41?
FAST-41 is a US federal program for projects considered strategically important enough to get coordinated, accelerated federal permitting.
This bypasses the multi-year, multi-agency queue most US mining projects get stuck in.
Only a small number of projects have ever received FAST-41 status since the program started with only a handful on the ASX.
We covered this news in a deep dive here and this news is what led the share price to go from 4.4c to as high as 8.4c in the days following: RML gets FAST-41 status from US government to fast track nationally strategic project. NASDAQ listing in 45 days.
This is the dashboard with the timeline:
(source)
$4.75BN capped Perpetua resources next door to RML had been in permitting limbo for many years, it actually began permitting in 2016, taking ~8 years. (source)
While it was well into the permitting process until receiving FAST-41, it was being constantly held up, it was selected for FAST-41 in April 2025 and by May 2025 was fully permitted.
So it wasn’t until it got involved in the FAST-41 program that it was actually able to get through this process (and has since begun construction).
So we see RML getting on the FAST-41 program as something that could accelerate the project by years.
What else is RML up to?
RML recently announced that drilling is set to get underway for gold at the Golden Gate area of the project.
RML’s phase 2 diamond drill program is for up to 45 holes across a total of ~13,700M of drilling, here is the announcement form last week, so we should get an update on this very soon:
(source)
This round of drilling will be 4X bigger than the 14-hole drill program RML ran last year (when it made its gold discovery).
The important differentiator is that it is with two diamond drill rigs - meaning RML can really test at depth extensions to its discovery and progress toward a JORC Mineral Resource Estimate targeted for Q1 2027 (subject to the drilling going well).
Phase 1 drilling at Golden Gate hit gold in every hole (14/14), with best intercepts including:
- 253.0m @ 1.50 g/t gold (HH-GG25-003C)
- 197.5m @ 1.26 g/t gold (HH-GG25-001C)
- 265.2m @ 0.60 g/t gold (HH-GG25-002C)
- 240.8m @ 0.64 g/t gold (HH-GG25-004C)
Then in February RML hit a second gold discovery at Golden Gate South with a hit of 99.1m @ 0.38 g/t gold from surface to end of hole in HH-GG25-013R.
(source)
So heading into Phase 2, RML has:
- Gold intercepts open at depth, along ~500m of strike.
- Two separate gold discoveries (Golden Gate North + South) across ~1.5km of strike
- A tungsten intercept already on the books at Golden Gate (HH-GG25-012R: 21m @ 0.06% tungsten including. 8m @ 0.14% tungsten)
- A historical Golden Gate Tungsten Mine (last mined 1980) that hasn’t been modern drilled
What we want to see next from RML
🔲 Phase 2 drilling at Golden Gate gold discovery (gold & tungsten)
RML has permits for a 45-hole follow-up program - up to 45,000 feet (13,700m) of core drilling at Golden Gate.
This is the program that should lead to a maiden JORC resource in Q1 2027.
RML has confirmed drilling is expected to begin next week. (source)
Here are the milestones we are tracking:
- ✅ Phase 2 permits secured (45 holes, 13,700m)
- 🔲 Phase 2 drilling commences (Next week - early May)
- 🔲 Phase 2 assay results
- 🔲 Maiden mineral resource estimate (targeting Q1 2027)
🔲 First ever drill program at Antimony Ridge (FAST-41 status now in place)
We also want to see RML drill test Antimony Ridge for the first time.
RML is planning up to 250 holes on the project.
Here are the milestones we are tracking for that project:
- ✅ FAST-41 status granted by White House
- ✅ Plan of Operations submitted to US Forest Service
- ✅ FAST-41 permitting process - (RML’s dashboard went live with the timeline). See that here
- 🔲 Bulk sampling of near-surface high-grade antimony from existing workings
- 🔲 Drilling of up to 250 holes to define scale of antimony system
🔄 NASDAQ listing
RML has already submitted its registration statement to the SEC and launched its ADR facility through Bank of New York Mellon.
RML expects to have its listing completed in “approximately 45 days”:
(source)
🔄Tungsten processing opportunity
After RML’s latest tungsten announcement, we are also looking forward to seeing RML progress its tungsten strategy.
Here are the milestones we are tracking:
- ✅ Johnson Creek Mill and tungsten stockpiles acquired
- ✅ High-grade tungsten assay confirmed
- 🔄 Sampling and assay program to define stockpile grade/tonnage
- 🔄 Offtake discussions with the US government and/or commercial buyers (confirmed recently underway) (source)
- 🔄 Metallurgical test work and process flowsheet development
- 🔄 Mill refurbishment assessment
Our US gold-antimony-tungsten Investment Resolution Minerals (ASX: RML | ORC: RLMLF) just announced metallurgical testwork from its Antimony Ridge project in Idaho.
(source)
This is the project that recently received FAST-41 designation by the US government.
AND the same project that has historically produced:
- During World War 1: RML’s project produced antimony.
- During World War 2: Antimony was produced again.
- In the 1960’s: There was even more Antimony production.
- And then between the 1950’s & 1980’s: Tungsten.
Today, RML showed that testwork on samples taken from the project returned high recovery rates with “virtually all of the stibnite would be captured in the rougher flotation concentration stage”.
We also noticed RML said it’s plan is to develop a “hydrometallurgy processing hub for antimony, as stibnite, in Idaho”.
So RML is already thinking about how to get the project back into production AND how the rocks can be processed using typically more environmentally friendly hydrometallurgy…
Although we are interested in the antimony, it is the sulphur recovery that is the key number because this shows how much of the stibnite (antimony bearing mineral) is being extracted from the samples.
RML managed to achieve a 99.5% sulphur recovery in rougher flotation indicates nearly complete recovery of the stibnite (antimony sulphide) from the sample.
So the result is yes, that the simple gravity/flotation circuit works, and most of the antimony from the stibnite is being recovered.
RML now has further works underway on this looking to bump up the concentrate grade from ~30% to ~50% antimony, this would be done through further concentration stages.
This complements RML’s antimony trioxide result we covered last month (RML produces antimony trioxide from Fast-41 status project in the US).
This is where RML produced a 99.38% antimony trioxide product using the conventional pyrometallurgical volatilisation process.
So now RML has metallurgy results validating both ends of the antimony processing pathway:
- Upstream: flotation concentrate recovery at 99.5% sulphur recovery / 76% antimony recovery (today)
- Downstream: 99.38% pure antimony trioxide via volatilisation (April)
So the early signs are that a clean, simple, conventional processing flowsheet from rock to refined product can be produced.
Importantly from a project that already has FAST-41 status from the White House.
What is FAST-41?
FAST-41 is a US federal program for projects considered strategically important enough to get coordinated, accelerated federal permitting.
This bypasses the multi-year, multi-agency queue most US mining projects get stuck in.
Only a small number of projects have ever received FAST-41 status since the program started with only a handful on the ASX.
We covered this news in a deep dive here and this news is what led the share price to go from 4.4c to as high as 8.4c in the days following: RML gets FAST-41 status from US government to fast track nationally strategic project. NASDAQ listing in 45 days.
This is the dashboard with the timeline:
(source)
$4.75BN capped Perpetua resources next door to RML had been in permitting limbo for many years, it actually began permitting in 2016, taking ~8 years. (source)
While it was well into the permitting process until receiving FAST-41, it was being constantly held up, it was selected for FAST-41 in April 2025 and by May 2025 was fully permitted.
So it wasn’t until it got involved in the FAST-41 program that it was actually able to get through this process (and has since begun construction).
So we see RML getting on the FAST-41 program as something that could accelerate the project by years.
What else is RML up to?
RML recently announced that drilling is set to get underway for gold at the Golden Gate area of the project.
RML’s phase 2 diamond drill program is for up to 45 holes across a total of ~13,700M of drilling, here is the announcement form last week, so we should get an update on this very soon:
(source)
This round of drilling will be 4X bigger than the 14-hole drill program RML ran last year (when it made its gold discovery).
The important differentiator is that it is with two diamond drill rigs - meaning RML can really test at depth extensions to its discovery and progress toward a JORC Mineral Resource Estimate targeted for Q1 2027 (subject to the drilling going well).
Phase 1 drilling at Golden Gate hit gold in every hole (14/14), with best intercepts including:
- 253.0m @ 1.50 g/t gold (HH-GG25-003C)
- 197.5m @ 1.26 g/t gold (HH-GG25-001C)
- 265.2m @ 0.60 g/t gold (HH-GG25-002C)
- 240.8m @ 0.64 g/t gold (HH-GG25-004C)
Then in February RML hit a second gold discovery at Golden Gate South with a hit of 99.1m @ 0.38 g/t gold from surface to end of hole in HH-GG25-013R.
(source)
So heading into Phase 2, RML has:
- Gold intercepts open at depth, along ~500m of strike.
- Two separate gold discoveries (Golden Gate North + South) across ~1.5km of strike
- A tungsten intercept already on the books at Golden Gate (HH-GG25-012R: 21m @ 0.06% tungsten including. 8m @ 0.14% tungsten)
- A historical Golden Gate Tungsten Mine (last mined 1980) that hasn’t been modern drilled
What we want to see next from RML
🔲 Phase 2 drilling at Golden Gate gold discovery (gold & tungsten)
RML has permits for a 45-hole follow-up program - up to 45,000 feet (13,700m) of core drilling at Golden Gate.
This is the program that should lead to a maiden JORC resource in Q1 2027.
RML has confirmed drilling is expected to begin next week. (source)
Here are the milestones we are tracking:
- ✅ Phase 2 permits secured (45 holes, 13,700m)
- 🔲 Phase 2 drilling commences (Next week - early May)
- 🔲 Phase 2 assay results
- 🔲 Maiden mineral resource estimate (targeting Q1 2027)
🔲 First ever drill program at Antimony Ridge (FAST-41 status now in place)
We also want to see RML drill test Antimony Ridge for the first time.
RML is planning up to 250 holes on the project.
Here are the milestones we are tracking for that project:
- ✅ FAST-41 status granted by White House
- ✅ Plan of Operations submitted to US Forest Service
- ✅ FAST-41 permitting process - (RML’s dashboard went live with the timeline). See that here
- 🔲 Bulk sampling of near-surface high-grade antimony from existing workings
- 🔲 Drilling of up to 250 holes to define scale of antimony system
🔄 NASDAQ listing
RML has already submitted its registration statement to the SEC and launched its ADR facility through Bank of New York Mellon.
RML expects to have its listing completed in “approximately 45 days”:
(source)
🔄Tungsten processing opportunity
After RML’s latest tungsten announcement, we are also looking forward to seeing RML progress its tungsten strategy.
Here are the milestones we are tracking:
- ✅ Johnson Creek Mill and tungsten stockpiles acquired
- ✅ High-grade tungsten assay confirmed
- 🔄 Sampling and assay program to define stockpile grade/tonnage
- 🔄 Offtake discussions with the US government and/or commercial buyers (confirmed recently underway) (source)
- 🔄 Metallurgical test work and process flowsheet development
- 🔄 Mill refurbishment assessment
