Shoki Kosai

To achieve stable supply and procurement of gold, it is crucial to focus on mining activities located upstream in the supply chain and to evaluate the associated supply chain risk. This study is the first to aim to quantitatively assess the supply chain risks associated with artisanal and small-scale gold mining (ASGM) activities. Through exhaustive and non-arbitrary identification of supply chain risk factors using econometric bibliometric analysis, 16 supply chain risk factors related to ASGM activities were identified and a supply chain risk framework for ASGM was developed. Identified supply chain risk factors are categorized into social, environmental, geopolitical, economic and technological dimensions. An index-based quantitative assessment of 63 ASGM engaged countries based on the framework identified Peru, Indonesia, and Mali as high supply chain risk countries. The assessment using the methodology of this study reveals ASGM engaged countries that had been underestimated and overlooked in existing studies. The results of quantitative supply chain risk dedicated to the ASGM engaged countries could assist companies to conduct due diligence on the more strengthened gold supply chain based on responsible sourcing.

An evaluation of resource efficiency by the transportation system is essential. Resource efficiency was examined from the perspective of mining activity in the form of resource intensity of transportation systems by combining transportation means and infrastructure. The framework of transport infrastructure was developed under a standardized classification to compare the entire transportation sector for various modes of transportation. This framework consists of links, support for links, nodes, fuel supply, and tanks for roadways, railways, aviation, and waterways. The developed framework was then applied to the Japanese transportation system, and resource efficiency in terms of passengers per vehicle was estimated by integrating means of transportation with associated infrastructure using the total material requirement as an indicator of mining intensity. It was identified that the transport infrastructure accounts for a high share of the resource intensity of passenger cars (15–30%) and railways (50–80%). Notably, even considering the massive mining demand for the development of transport infrastructure, the resource efficiency of railways is the highest among various transportation modes.

Material flow analysis of plastics has attracted considerable attention for achieving sustainable production and consumption. However, the direct weights of each plastic have been analyzed alone, not considering the amount of natural resources as inputs for plastic production. Therefore, we analyzed the cradle-to-gate resource intensity of 21 types of plastics in terms of mining activity, using the total material requirement under the life cycle concept. It was found that the resource use for plastic production differs by up to approximately 10 times depending on the plastic type. By applying these findings to the material flow analysis of some countries and regions, we found that the quantity of natural resources was more than 20 times the original weight attributed to plastic production. By comparing resource use with greenhouse gas emissions, plastics with higher greenhouse gas emissions were found to have higher resource use, indicating a positive correlation, whereas the opposite trend was also found for some plastics. Considering plastic alternatives, we found that the quantity of natural resources in plastic-based shopping bags is nearly equivalent to that in paper-based bags, whereas that in plastic-based straws is greater than that in paper-based bags. Focusing only on the direct weight of plastic may mislead the decision-making process.