Red Mountain Mining ltd (ASX:RMX) Hits Highest Antimony Grades to Date up to 39.3%

Highlights:

• Rock chip samples collected during follow up auger soil sampling at Oaky Creek South
  returned multiple strong antimony and gold results including:
  o 39.3% Sb and 0.16g/t Au
  o 33.5% Sb and 1.09g/t Au
  o 19.4% Sb and 0.52g/t Au
• The results confirm the potential of the Oaky Creek prospect to host a major orogenic
  antimony-gold camp, with mineralised samples now collected over a strike extent of 500m at Oaky Creek South and 700m at Oaky Creek North, with significant additional untested
  extensions indicated by the ~1.5km long antimony soil anomaly at Oaky Creek North.
• Analytical results are expected later this month for 10m-and 20m-spaced hand auger soil
  sampling completed at Oaky Creek South.
• Assay results are also pending for initial 50m by 100m spaced soil sampling at the East Hills antimony prospect in the southern portion of EL9732.
• Red Mountain is well positioned to continue aggressive exploration across its Antimony and Gold assets in Australia and North America following recent oversubscribed placement.
• The company continues to assess value accretive critical metals assets in North America with funding in place.

Overview:

Red Mountain Mining Limited announced rock chip analyses for 18 rock chip samples collected during a recent hand auger soil sampling campaign at the Oaky Creek prospect within the Company’s 100% owned Armidale antimony-gold project (EL9732) in the Southern New England Orogen of northeast New South Wales.

The highest Antimony grades have been delivered from these results which correlate to previous soil samples. Analytical results of up to 39.3% Sb and 1.09g/t Au have been received for rock chip samples from the Oaky Creek prospect in the northern portion of RMX’s tenement (Figure 1), where the company previously reported antimony in soils results of up to 333ppm Sb1 and rock chip values of up to 28.3% Sb2 and 0.54g/t Au3

Rock chip sampling was undertaken during the collection of approximately 250 hand auger soil samples spaced at 10m and 20m across the Oaky Creek South prospect (Figures 2 and 3), following up antimony soil anomalies defined by initial 50m x 100m spaced soil sampling reported in June 2025.
Analytical results for the hand auger sampling program are expected to be received before the end of October

Rock chip samples were analysed at Intertek’s Townsville laboratory for Sb, Ag, As and W using sodium peroxide fusion and ICP-MS finish, and for Au using a 50g fire assay charge and ICP-OES finish. All analytical results are listed in Table 1, and gold and antimony results are shown in Figures 2 and 3.

Five rock chip samples collected over the soil anomaly ~500m northwest of the historical workings at Oaky Creek South returned antimony values of >1% Sb, with best values of 39.3% and 33.5% Sb (Figure 2), which are the highest values recorded to date for the Oaky Creek Prospect. Four of these samples also returned results >0.1g/t Au, with a peak value of 1.09g/t Au (Figure 3), which is the first result of over 1g/t Au recorded for Oaky Creek. Although four of the five samples are float, all lie within ~100m of the crest on the western flank of a low northwest-trending ridge and none are thought to have been transported far from source. As can been seen in Table 1, arsenic values are elevated in samples containing anomalous antimony and gold, which is typical of orogenic antimony-gold systems in the New England Orogen. However, tungsten values from the rock chip samples are all less than 10ppm and all silver results are less than the detection limit of 5ppm Ag.

The antimony-and gold-rich rock chip samples collected ~500m northwest of the Oaky Creek South workings confirm the potential of the Okay Creek prospect to host a major orogenic antimony-gold camp, with mineralised samples now collected over a strike extent of 500m at Oaky Creek South and 700m at Oaky Creek North, with significant additional untested extensions indicated by the ~1.5km long antimony soil anomaly at Oaky Creek North (Figures 2 and 3).

Next Steps
Subject to positive results for the pending assays from Oaky Creek South, RMX plans to undertake a similar program of hand auger soil and rock chip sampling over the Oaky Creek North soil anomaly to define prospective drill targets.

As previously reported4 , soil and rock chip sampling is also planned for the Horsley Station and Horsley North gold targets, where land access has now been secured. As reported in August 20255, RMX is also working to secure land access to ground truth stibnite and jarosite spectral anomalies across EL9732, in particular those that lie adjacent to known mineralisation and/or are along the known major Peel, Namoi and Cobbadah faults.

Full ASX Announcement: https://hotcopper.com.au/threads/ann-highest-antimony-grades-to-date-at-armidale-project.8803615/
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