**1. Introduction**

Three-dimensional (3D) geological modeling is a prominent technology that can be used to calculate or extract key parameters from 3D information on ore deposits [1]. Applying the theory of a metallogenic system, combined with multi-parameter or multi-source (geological, geophysical, geochemical, and hyperspectral) and multi-method modeling and

**Citation:** Liu, Z.; Zuo, L.; Xu, S.; He, Y.; Wang, C.; Wang, L.; Yang, T.; Wang, G.; Zeng, L.; Mou, N.; et al. 3D Multi-Parameter Geological Modeling and Knowledge Findings for Mo Oxide Orebodies in the Shangfanggou Porphyry–Skarn Mo (–Fe) Deposit, Henan Province, China. *Minerals* **2022**, *12*, 769. https://doi.org/10.3390/min12060769

Academic Editor: Yosoon Choi

Received: 13 May 2022 Accepted: 12 June 2022 Published: 17 June 2022

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analysis of a 3D ore-forming geologic body, the capabilities of quantitative and big data collation, mineral exploration, and mining are greatly improved [2,3]. It has been proved that 3D GIS or modeling packages (e.g., Micromine, GOCAD, and Surpac) are excellent means of data representation and interpretation [4].

3D geological modeling provides distinct advantages in assisting geologists in determining the geological background, mineralization, and mineral exploration in a comprehensive and effective manner [5–18].

Porphyry–skarn-type molybdenum (Mo) deposits are one of the strategic and economic resources in China. The East Qinling Mo belt (EQMB; Figure 1B) is referred to as one of the most significant Mo provinces in the world, containing reserves of about 6 Mt Mo [19,20]. The Shangfanggou Mo–Fe deposit is an important deposit in the East Qinling Mo polymetallic metallogenic belt. It is adjacent to the Nannihu–Sandaozhuang Mo–W polymetallic deposit in the northeast (Figure 1D), which together constitute the main body of the Nannihu Mo ore field in Luanchuan district, China. In 2000, the estimated Mo reserves of the three major deposits (Nannihu, Sandaozhuang, and Shangfanggou) were about 2.4 <sup>×</sup> <sup>10</sup><sup>6</sup> tons (with an average Mo grade of 0.109%) [21], while the Shangfanggou deposit contained 0.72 million tons of Mo and 59.91 million tons of Fe metal, with average grades of 0.135% Mo [22,23] and 30.14% Fe [24].

Although there have been many studies on 3D geological modeling of the Luanchuan ore district [25,26], they have been insufficient to construct 3D multi-parameter geological modeling of the study area. Moreover, the formation of the Shangfanggou porphyry–skarn deposit is mainly controlled by strong tectonic magmatic movement in the Mesozoic. The complex geological background, multiple geological factors, and multi-scale and multiformat data sources pose challenges to 3D geological modeling and deep prediction.

Currently, the industrial Mo ores used by the mine are mainly the primary molybdenite; the onefold Mo oxide ores nearly cannot be recycled and utilized because they are difficult to beneficiate, and the ore-forming process (supergene oxidation process) of this kind of ore type also lacks research. In recent years, global Mo ore output has tended to decline, and the situation of rapid economic and social development has led to a demand for Mo. Therefore, it has become an important and urgent topic to study the genesis and prospecting of Mo ores in the oxidation zone and to utilize Mo oxide ores comprehensively and efficiently. On the basis of previous studies, this paper systematically discusses the mineralization and oxidation process of Mo orebodies in the Shangfanggou porphyry– skarn Mo–Fe deposit. The temporal–spatial–genetic correlation and exploration constraints of magnetite and gangue minerals to Mo and Mo oxide orebodies are discovered, and the distribution characteristics of the oxidation zone are further investigated (Figure 2). These findings provide a reference for the genesis and exploration, as well as the recovery and utilization, of oxidized ores for mining and beneficiation of the mine.

#### **2. Geological Setting**
