Operations are conducted under Indonesian production permits and supported by group-operated processing, refining, and stockpile facilities.
OMS Bromo — sea-mined sand cargo in the hold, Banten coast.
The group's metal mineral mining permit covers a 1,972-hectare offshore concession authorised for production by the Banten provincial authority, with horizon for renewal under existing law.
Recovered ore is processed through a circuit that includes crushing and grinding, classification, leaching, carbon-in-leach (CIL), elution and electrowinning, and final smelting to doré bullion. The plant is operated within the group, supported by on-site assay laboratory capability and dedicated stockpile logistics.
A single integrated circuit reduces handling between extraction and refined output, supports tighter quality control, and aligns with Indonesia's regulatory priority for in-country mineral processing.
Group mineral-processing facility — leach tank circuit. Footage courtesy Graha Makmur Coalindo group.
The mining approach is matched to ore type. Near-surface oxide and transition material is recovered through open-pit methods; deeper, higher-grade fresh ore is targeted using underground sublevel-stoping techniques where supported by the orebody. The two methods are complementary and allow the company to extract material across the full mineralisation profile of the concession.
Operations are supported by group-level infrastructure: an integrated processing plant, on-site power, water management, laboratory and assay services, and stockpile logistics. The company's stockpile facility is positioned at Krakatau Bandar Samudera in Cilegon, providing direct access to maritime export logistics for refined output.
Research and exploration activity is conducted in cooperation with Indonesia's national geological research bodies, including ongoing programmes related to marine mineral exploration in the Indonesian Indian Ocean.
Working vessels, dive teams, and dredge equipment deployed in the company's marine concession area off the Banten coast.
Surface entry — marine teams deploy from working vessels.
Offshore operation — divers descending the anchor line.
Marine concession — working the Indonesian seabed.
