Our Projects

Sihayo Gold



Sihayo Gold Limited
North Sumatra, Indonesia

Sihayo Gold Limited owns 75% interest in PT Sorikmas Mining, a gold exploration company based in Indonesia, where there is a Contract of Work with the Indonesian Government to explore in the North Sumatra, 80km South-East from Martabe Gold Mine. Sihayo Gold Limited required extensive work to improve the technical definition of the Sihayo Gold Project to allow for project financing to fund the development of the project.

Sihayo Gold Limited engaged Primero over other competitors due to our excellent existing working relationship with PT Sorikmas Mining. Our link with PT Sorikmas Mining came from our involvement in the design and construction of the Tujuh Bukit Project in Indonesia. Further to this Primero have the capability and capacity to ensure the level of detail and credence is adequate in the Feasibility Study to attract a funding partner to finance and develop the project.

Primero was involved in the development of the process plant throughput ramp-up capacity where it is assumed the process plant design will be a standard Carbon in Leach (CIL) circuit, and an easy transfer to commissioning.


Primero’s scope of work involves the review and update of the process plant design and provide American Association of Cost Engineering (AACE) capital cost estimate (CAPEX) and operating cost estimate (OPEX) to a class 3 estimate ±15% for the process plant. It was determined during the optimization studies, that a larger mill size was required to operate 2Mtpa on all ore types to allow for more flexibility. A crushing station was also added to the process plant design to effectively manage the Oxide ore, a surge bin and emergency stockpile were also other major additions to the Definitive Feasibility Design.


The project optimisation study has resulted in a more robust project design for Sihayo Gold Limited, and helped identified further pathway opportunities. This flexibility and de-risk in design have allowed Sihayo Gold Limited to commence a strategic review process to attract funding to further develop the project. There are plans to establish a beneficiation plant as the project development progresses.