Copper deposit development potential on the Qinghai-Xizang Plateau in China based on the pressure-state-response framework

Major factors of copper deposit development potential

The pressure layer (P layer) highlights the supporting role of infrastructure in resource development. The high index weights of traffic accessibility (P3) and electric power (P5) (Table 1)indicate the importance of infrastructure development for the exploitation and development of mineral resources, reflecting that in remote and geographically complex areas like the QXP, the improvement of infrastructure is key to enhancing the efficiency of mineral resource development and reducing operational costs^45,46, and the corresponding weight settings also ensure that these indexes are fully considered in the development potential assessment. In addition, the relatively low weight of habitat quality index (P1) does not imply that the habitat quality of the Qinghai-Xizang Plateau’s habitats is high. Instead, it indicates that the variability in habitat quality among the copper deposits is significantly lower compared to the variability observed in other indexes. This suggests that while environmental considerations are important, the differences in environmental conditions at the deposits may be less diverse or pronounced than the differences observed in other factors such as geological features, economic policies, or infrastructure.

In the state layer (S layer), the weight of the ore deposit resource scale index (S3) is the highest, followed by the regional metallogenic condition index (S1), indicating the central role of geological surveys and resource assessments in copper mineral resource exploration and development. This matches the actual development situation of copper deposits on the QXP region, highlighting the importance of mineral resource scale and potential economic value in the evaluation system.

In the response layer (R layer), the highest weight of the economic structure (R1) indicates the significant impact of economic strategies on the exploration and development of copper mineral resources. This weight helps to evaluate and guide the adjustment of the economic structure and mining development strategy on the QXP, to promote the rational resource exploitation and the balanced development of the regional economy. This suggests that mining activities have a significant impact on the optimization of the regional economic structure and economic development^47,48. Rational policy support and economic adjustments are crucial for sustainable resource development⁴⁹. In addition, although the weights of environmental policy indexes (R3) and green development index (R5) are low, they still indicate the necessity to consider environmental protection and green development requirements throughout the copper mineral resource exploitation, indicating that it is essential to guarantee ecological sustainability and respond to societal needs for environmentally sound mining practices, concurrently with the pursuit of economic gains⁵⁰.

In this study, the weight results of the indexes in the PSR model reflect the scientific nature of the evaluation of the development potential of copper mineral resources, ensuring that the evaluation results can truly assess the advantages and risks of resource exploitation and development, and effectively guide future resource management and policy optimization.

Evaluation of spatial pattern on PSR

Based on the weight results (Table 1) of the 16 indicators in the PSR model, a systematic evaluation of the copper mineral resources on the QSP was conducted. This evaluation revealed the comprehensive impact of natural conditions, economic and social factors, infrastructure, resource status, and development strategies on the utilizability of copper minerals in the region. The P and R scores were evaluated across the entire QXP. Following this, the specific P and R scores for each copper deposit were extracted based on the geographical positioning of the deposits within the overall results. In contrast, the S scores were evaluated at the individual deposit level, reflecting the conditions and characteristics unique to each site.

The pressure scores of copper deposits show significant spatial heterogeneity (Fig. 4). The copper deposits with high P scores are primarily concentrated in central and western Xizang, central and western Qinghai, and southern Xinjiang, while those with low P scores are mainly distributed in eastern Xizang, eastern Qinghai, western Sichuan, and northwestern Yunnan. The high P score reflects that the areas have poor ecological environment quality, unfavorable terrain conditions, and relatively incomplete infrastructure such as transportation conditions and power supply, indicating a high level of development pressure. In areas with fragile ecological environments or limited resource conditions, more attention needs to be paid to the sustainability of environmental protection, while the areas with abundant resources and more complete infrastructure can be considered as potential areas for the utilization of copper mines.

Spatial pattern of pressure (P), state (S), and response (R) scores. The circles represent the copper deposits, and their colors represent the numerical levels of the corresponding indicators for each deposit.

The state scores of copper deposits directly reflect the resource potential of the copper deposits. Copper deposits with high S scores are relatively few and are predominantly located in the eastern and central parts of Xizang and northwestern Yunnan (Fig. 3). Copper deposits with low S scores are primarily situated at the border area between Gansu and Qinghai provinces and in the northwestern Sichuan region near the edge of the QXP. Notably, the eastern Xizang and northwestern Yunnan areas, which are also regions of concentrated low P score deposits, demonstrate good potential for development. The regional ore-forming conditions and the regional resource potentials formed during long geological processes, which are difficult to change. Therefore, for deposits that have completed exploration, under the condition that there is no significant advancement in the existing exploration and mining technology, increasing the degree of exploration may improve the resource status to some extent, but the change will not be very significant.

The distribution of response scores for copper deposits is more intricate (Fig. 3). Copper deposits with high R scores are mainly distributed in the westernmost Xinjiang region, central Xizang, and central and northwestern parts of Qinghai on the QXP, indicating that these regions have suitable policy response conditions for mineral resource development. The high R score indicates that the copper areas are more responsive in terms of economic structure, the proportion of the population employed in mining, environmental policies, mining policies, and green development index compared to other areas. This may be due to the more mature economic environment, more specialized mining labor force, more comprehensive environmental protection measures, more favorable mining policies, or a higher level of green development in these areas, which lead to favorable conditions for the sustainable development of copper resources. Copper deposits with low R scores are predominantly located in the western part of Xizang and the eastern and southwestern parts of Qinghai, where local environmental protection policies and mining policies restrict the exploitation of mineral resources.

The PSR evaluation results of 304 copper deposits on the QXP reflect the complexity and multidimensionality of regional environmental management. This situation requires decision-makers, researchers, and resource development agencies to make decisions based on accurate copper deposits data, taking into account both the self-regulation capacity of the ecosystem and the needs of economic development and society.

Copper resource development potential on the QXP

In an ideal scenario, copper deposits with low P score but high S and R scores are expected to have good development potential. However, comparing these three variables alone is difficult to accurately assess the copper deposits, hence it is very necessary to introduce the CEPI to evaluate the potential. The CEPI values of the copper deposits on the QXP were calculated based on the P, S and R scores (Fig. 5). The overall CEPI values fall within a narrow range between 0.03 and 0.032. Approximately 63% of the copper deposits exhibit a relatively low level of comprehensive potential, with their CEPI values falling below the average value of 0.053.

Only 10% of the copper deposits have a CEPI value exceeding the significant threshold of 0.10. These deposits are notably concentrated along the southern margin of the Gangdese-Nyainqentanglha metallogenic province in the south-central Xizang, as well as in the southeast segment of the Sanjiang metallogenic province in eastern Xizang and northwestern Yunnan. Among these deposits with high CEPI values, super-large copper deposits (Cu ≥ 2.5 Mt) constitute an approximate share of 13%, while large copper deposits (0.5 Mt ≤ Cu < 2.5 Mt) account for about 27% of the total. The CPEI values have strong spatial correlation with the scale of these copper deposits. These metallogenic provinces undergone long and complex geological processes, leading to a high concentration of copper resources and the formation of high-quality copper polymetallic ore deposits. However, some medium and small-scale copper deposits have CPEI values greater than some medium even large-scale copper deposits. These deposits are located around the high CPEI deposits mentioned above, once again confirming that these areas have good potential for mineral resource utilization. This also reflects the combined effect of natural conditions and development feasibility. In areas with convenient transportation, relatively stable ecological environment, and relaxed policies, even if the scale of the deposit is medium, it can still obtain a high CPEI value, which is suitable for implementing small-scale and environmentally friendly development strategies to balance the needs of resource utilization and ecological protection.

Spatial pattern of the CEPI scores for copper deposits on the QXP.

Major obstacle to copper deposit development potential on the QXP

The spatial pattern of the PSR obstacles of copper deposits on the QXP were evaluated (Fig. 6). The copper deposits with high P obstacle degree are notably concentrated in the central and western Xizang, northern and western Qinghai, and the southwestern part of Xinjiang. The high S obstacle degree copper deposits are particularly concentrated in northwestern Yunnan, and eastern Qinghai. The deposits with high R obstacle degree are chiefly situated in the northwestern Yunnan, eastern Qinghai, central Xizang, and the junction area between Xizang and Sichuan. These results provide a clear spatial distribution of the obstacle degrees across different regions of the QXP, indicating areas that may require more focused attention and strategic planning for the sustainable development of copper mining activities.

Spatial pattern of the obstacle degrees for copper deposits on the QXP. The circles represent the copper deposits, and their colors represent the numerical levels of the corresponding indicators for each deposit.

The potential obstacles to copper deposit development potential play important roles in formulating targeted mineral resource exploitation and utilization policies to enhance economic development while maintaining sustainable economic and social development. Seven obstacle types are classified with decision-making process shown in Fig. 2, providing a direct assessment of the relative influence of pressure, state, response on the development potential of copper deposits on the QXP (Fig. 7).

The balanced type is the most common obstacle type and indicates that the obstacle degrees of P, S and R are relatively balanced, with no particularly prominent layers. The balance type is the most common type on the QXP. The copper deposits of this type, accounting for 36% of the total number of copper deposits on the QXP, are main distributed in central Xizang, and southwestern part of Xinjiang. These deposits are mainly small-scale, often with large and close P, S and R obstacle degree values, which result in poor development potential.

Spatial pattern of the obstacle types for copper deposits on the QXP.

The P dominated obstacle type indicates that the development potential of copper deposits is primarily influenced by external pressures. This do not necessarily mean that the natural environment is fragile, the terrain is complex, or the infrastructure is inadequate, but rather that the obstacle to copper deposit development potential from pressures is greater compared to the state and response measures. The copper deposits of this type are mainly distributed in central Xizang, accounting for 2% of the total number of copper deposits on the QXP.

The S dominated obstacle type suggests that the copper deposits is mainly affected by geological conditions or the resources themselves. Most of these deposits have smaller scale of copper resource. Some large copper deposits are also of the S dominant obstacle type, indicating that pressure and response in these areas have a relatively smaller impact on the development potential of copper deposits. The copper deposits of this type are primarily located in central Xizang, central and northern Qinghai, the border area between Xizang and Sichuan, and eastern Sichuan, accounting 20% of the total number of copper deposits.

The R dominated obstacle type indicates that these copper deposits are mainly influenced by response, which is probably related to local socio-economic conditions or policy environment constraints. These deposits have good resource potential and external pressure conditions, making response the most significant obstacle. The copper deposits of this type are mainly distributed in the border area among Xizang, Yunnan and Sichuan, accounting for 5%.

The dual-layer dominated types show that the impacts of indexes from two layers on the development potential of the copper deposits are close and significantly greater than the indexes from the rest layer. Among them, the copper deposits of P-S and P-R dominated types are relatively few, accounting for 9% and 4% of the total number of copper deposits on the QXP, respectively. In contrast, the copper deposits of S-R dominated type account for 24%, mostly medium-sized copper resource scale, and mainly concentrated in eastern Xizang and northwestern Yunnan.

By integrating P, S and R layers, and selecting some deposits as case studies, this study discussed the importance of understanding the interactions between these layers when assessing the overall development potential for copper deposits on the QXP.

The copper deposits such as Pulang, Yulong, Jiama, Qulong, Xiongcun, Zhuno, and Duobuzha are all super-large copper deposits with exceptionally high resource potential. However, these deposits are of various obstacle types (Fig. 7). The Pulang copper deposit is situated in the northwest of Yunnan, the region has superior ecological environment conditions and relatively complete infrastructure construction, which result in a comparatively low level of development pressure (P). Conversely, the R layer, particularly stringent environmental policies, emerges as the predominant influence on copper resource development. These policies escalate the costs and complexities associated with mining operations, thereby presenting an P obstacle type. The Qulong and Jiama copper deposits in central Xizang are situated in areas with more fragile ecological conditions and less developed infrastructure. Although their R layers are relatively weaker compared to Yunnan, they have relatively little impact on resource development compared with their own P layers, so they present the P obstacle type. Regarding the Xiongcun, Zhuno, and Duobuzha copper deposits, despite possess favorable geological conditions. They face significant development pressure, and their R layers also have resistance to resource development. Both factors exert a considerable influence on resource development, leading to a composite obstacle type of P-R.

It is evident that it is not the absolute value of a single layer that determines the type and potential of a copper deposit, but rather a holistic assessment that takes into account the relative relationships between the three layers. This reference case illustrates how the PSR framework can be effectively applied to evaluate copper resource development potential and underscores the interconnectedness of the three layers. These findings emphasize the necessity of adopting a holistic approach in mineral resource assessment, effectively capturing the complexity and interplay between different indicators across multiple layers. Geological conditions, as well as socio-economic and environmental factors, must be carefully considered to provide a more comprehensive and accurate assessment of the copper deposit development potential on the QXP.