High Value Synthetic Diamond Manufacture

Additional test work demonstrates strong conversion yields and economically viable non-China production potential

Blencowe Resources Plc (LSE: BRES) is pleased to announce the results of additional test work confirming that graphite concentrates from the Orom-Cross Project are suitable for the manufacture of synthetic industrial diamonds, further validating the quality, versatility and downstream optionality of the Company's graphite feedstock.

The test work was undertaken by American Energy Technology Co. ("AETC") in Chicago and forms part of Blencowe's value-addition programme focused on demonstrating commercially viable, non-China downstream applications for Orom-Cross graphite.

Crucially, the test work achieved a diamond conversion yield of 53.6wt%, exceeding the typical industry benchmark of approximately 50%. AETC notes that this threshold is widely regarded as critical in determining whether synthetic diamond production can be undertaken economically outside China, given the highly competitive cost structure of the industry. Conversion yields below this level typically necessitate lower-cost Chinese processing to remain viable.

Production of industrial diamonds provides Orom-Cross with another significant value-adding enhancement opportunity beyond sale of graphite as concentrates and Blencowe will be seeking offtake opportunities in this sector ahead as it continues to drive towards first production.

Synthetic Diamond Test Work - Highlights

• Successful synthesis of robust industrial diamonds from Orom-Cross graphite concentrate
• All diamonds produced were mono-crystalline, a higher-value structure than polycrystalline alternatives
• Average particle size of 50-60 microns, with oversized diamonds up to 350-500 microns
• Conversion yield of 53.6wt%, supporting cost-competitive production outside China

AETC further observed that many natural graphites, including several deposits across East Africa, are less suitable for synthetic diamond manufacture due to thicker, less compressible flake structures, which inhibit efficient diamond formation. In contrast, the fine, compressible flake characteristics of Orom-Cross graphite proved highly conducive to diamond synthesis, representing a distinctive quality signature of the deposit.

Strategic Context

Synthetic diamond manufacture is a specialised, high-value industrial market where feedstock quality and conversion efficiency directly influence cost competitiveness. These results confirm that Orom-Cross graphite meets the technical thresholds required to support economically viable diamond production outside China, opening additional downstream pathways alongside the Company's core battery and energy transition strategy.

This optionality further differentiates Orom-Cross as a high-quality, non-China graphite source, aligned with increasing Western focus on secure supply chains, local processing and advanced manufacturing.

Importantly, the confirmation of multiple high-value end markets strengthens the overall Orom-Cross development case and supports Blencowe's ongoing funding and offtake processes. In parallel, the Company continues to progress drilling and resource definition across the project, with remaining assay results from the Iyan and Beehive programmes expected to be reported progressively, building toward sequential JORC resource updates.

Cameron Pearce, Blencowe's Executive Chairman commented:

"This work highlights a fundamental characteristic of Orom-Cross graphite: its quality extends beyond battery applications into demanding industrial uses where conversion efficiency and cost competitiveness are critical. Achieving mono-crystalline diamond formation at conversion yields above industry benchmarks reflects the compressibility and structural integrity of our graphite, which continues to differentiate the project.

As further drill results and technical validation are delivered, Orom-Cross continues to mature as a scalable, high-quality graphite development. This progress strengthens the underlying project fundamentals and is directly supporting funding and offtake discussions currently underway, as we advance toward the next resource update."