South Africa--Bushveld). In the case of Co, the world land-based resources are about 25 million tonnes [8] and occur mainly in sediment-hosted stratiform copper deposits in Congo and Ni-bearing laterite deposits.  
The largest resources in laterite deposits have been found in New Caledonia (23%; 37.0 \(\times\) 10\({}^{6}\) t), Philippines (17%; 27.4 \(\times\) 10\({}^{6}\) t), and Indonesia (16%; 25.8 \(\times\) 10\({}^{6}\) t) [9; 10]. In 2020, Ni production from laterites deposits achieved 69% [9]. Indonesia is one of the world's major suppliers of nickel from laterite deposits, and most of the resources are located in the Molucca and Sulawesi regions. Despite numerous discoveries of laterite deposits in Indonesia, few investigations have been made into the geochemical characteristics of these deposits [11; 12; 13; 14]. New research of Indonesian laterites has focused on the immobilization/recrystallization and enrichment of critical raw materials (i.e., Co, REE, Pt, and Pd) in the laterite profile based on mass-balance [15]. Understanding the geochemical processes leading to metal enrichment in different zones of the profile may contribute to more effective exploration of deposit and subsequent metallurgical processes.  
The Northern Molucca, including Halmahera, is the least geologically studied part of Indonesia. So far, exploration has been conducted here for lateritic nickel deposits, epithermal vein gold deposits, and porphyy copper-gold deposits. Only exploration of the first two types of deposits has been successful. Recognition of lateritic Ni and Co deposits was initiated in 1969 by the Japanese INDECO consortium in the Halmahera-Waigeo ophiolite terrane area. Geological works have discovered the Gebe deposit, estimated at 20 Mt of silicate ore and containing an average of 2.61 wt% Ni and 66 Mt of oxide ore averaging 1.25 wt% Ni. A laterite deposit was also found on Obi Island, estimated at 88 Mt with an average content of 1.20 wt% Ni. The Gebe Island deposit was later developed by Indonesian state-owned company PT Antam. PT Anam has also been exploring the Tanjung Buli deposit located in East Halmahera since 1981 [16]. Resources at the Gee silicate ore deposit are estimated at 31.4 Mt with an average content of 2.4 wt% Ni, and at the Tanjung Buli deposit at 25 Mt with an average content of 2.4 wt% Ni. Resources have also been documented at the Sangaji deposit of 33 Mt at an average of 1.40 wt% Ni and 0.19 wt% Co [17]. However, the largest known nickel-bearing laterite deposit is located in the central part of Halmahera. In this area, a project of the Weda Bay Nickel Project is being implemented covering about 55,000 ha, owned by the company Eramet and Mitsubishi Corporation and PT Antam with estimated at 139 Mt resources with an average content of 1.59 wt% Ni. It was discovered in 1995 and the first boreholes in the deposit were drilled by Strand Minerals Pte. Ltd. in 1996 [18]. The exploration history of Ni deposits on Halmahera to date is very promising and it is highly probable that, in the interior of the island in areas of favorable morphology, lateritic caps have formed on ultramafic rocks that may be economically viable to exploit [19].  
In this study, the Ni-rich laterite deposits in Halmahera, Indonesia were investigated to: (1) determine the mineral and chemical composition of the ore horizons, (2) mineral resource estimate, and (3) distribution and characteristic of critical raw materials (CRMs). Identification of mineral ore, quality, and resources will enable forecasting of mining and processing efficiency.