Sumedang, February 18, 2026 — PT Sumbawa Timur Mining (STM) donated core samples of the Onto Deposit to the Faculty of Geological Engineering (FTG) at Universitas Padjadjaran (Unpad) to support the development of geological research. The core samples were accompanied by a booklet titled Geological Learning from the Onto Deposit and a scientific poster titled Onto High Sulphidation-Porphyry Copper Project to deepen the context of deposit studies. The handover ceremony of all educational materials took place at the Faculty of Geological Engineering Dean’s Building, Unpad Jatinangor Main Campus.
The Onto Deposit is a copper-gold deposit discovered by STM’s exploration team in the Hu’u Project area, Dompu Regency, West Nusa Tenggara Province. The deposit is located in a dense mountainous area, about 500 meters below the surface, hidden beneath volcanic rocks without signs of mineralization. The discovery was achieved through drilling to a depth of 800 meters after detailed mapping, river sediment and soil sampling, and airborne geophysical surveys—including LiDAR, magnetic, and radiometric methods.
The innovative exploration methods used by the Onto Deposit discovery team in overcoming technical challenges earned them global recognition. In 2025, the Prospectors and Developers Association of Canada (PDAC) awarded the Thayer Lindsley Award to the Onto Deposit discovery team, affirming that this discovery is one of the most significant in the past two decades. STM intended to share this important discovery with FTG Unpad to enrich the knowledge of earth sciences.
The Onto Deposit core samples handed over to FTG Unpad represent lithological variations, hydrothermal alteration systems, and mineralization patterns that form the basis for resource evaluation as well as technical and economic feasibility of the Hu’u Project. In the academic environment, these materials are used to train observation, analysis, and interpretation of geological data based on field evidence.
Meanwhile, the Onto Deposit booklet contains a summary of geological evolution, characteristics of mineral-bearing rocks, types of alteration, and descriptions of mineralization in the submitted core samples. The Onto Deposit scientific poster presents visualizations of lithology, high sulphidation alteration systems, porphyry, and genetic models of the Onto Deposit. These materials are designed to bridge classroom theory with field exploration practice.
Dean of FTG Unpad, Boy Yoseph (left), and STM Exploration Manager, Galih Perdana (right), signed a cooperation agreement for the handover of Onto Deposit core samples along with supporting educational materials.
Dean of FTG Unpad, Dr.Eng. Boy Yoseph Cahya Sunan Sakti Syah Alam, S.T., M.T., stated that this collaboration provides concrete added value to academic processes. “We appreciate the contribution of PT Sumbawa Timur Mining through the handover of Onto Deposit core samples along with supporting educational materials. This collaboration enriches learning and research facilities at FTG Unpad, while opening opportunities for students and lecturers to understand geological and exploration processes directly from industry practices,” he said.
In addition, Boy Yoseph added that the core samples serve as an applied learning resource for students to understand the relationship between theory and exploration practice, including in mineralogy and petrography practicums. This real-case-based approach is considered important to build analytical competence and scientific accuracy among future geologists. He hopes this collaboration will further enrich students’ learning experiences.
Head of Communications STM, Cindy Elza, stated that this initiative is part of the company’s commitment to supporting the development of geological research in Indonesia. “Responsible exploration always begins with a scientific approach. We hope this collaboration can strengthen learning based on real data while building long-term partnerships between industry and educational institutions,” she said.
Through this collaboration, universities gain access to primary data and materials, while industry gains academic partners for the development of earth science research. This synergy encourages structured and sustainable knowledge exchange. The initiative is expected to support the strengthening of human resources who are theoretically strong and skilled in field data analysis and mineral discovery evaluation.
The collaboration between STM and FTG Unpad is not the first. For example, in May 2025, FTG Unpad conducted a study visit to the Hu’u Project, involving lecturers and students from the University of Geneva. The activity opened space for cross-institutional scientific discussions and broadened insights into copper-gold exploration practices in Indonesia. This series of collaborations reflects a shared commitment to building sustainable synergy.
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About PT Sumbawa Timur Mining
PT Sumbawa Timur Mining (STM) is a joint venture company between PT Aneka Tambang Tbk (20%) and Eastern Star Resources Pty Ltd (80%). STM manages the Hu’u Project, a copper exploration project operating under a 7th Generation Contract of Work (CoW) located in Hu’u Subdistrict, Dompu Regency, West Nusa Tenggara Province, Indonesia.
The CoW area also contains geothermal resources. To explore this potential, STM established its affiliate company, PT Sumbawa Timur Geothermal, which has received a Geothermal License (IPB) from the government. STM continues its journey toward realizing its vision of becoming a world-class copper mining operation powered by renewable energy.
For more information, please contact the STM Communications Team.
