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PhD Defence Yanyan Xue

sustainable urban mining: the case of china

Yanyan Xue is a PhD student in the department of Governance and Technology for Sustainability (CSTM). Her supervisors are prof.dr. J.T.A. Bressers from the faculty of Behavioural, Management and Social sciences (BMS) and prof.dr. Z.G. Wen from the Tsinghua University, China.

As society and economies grow with the increasing industrialization and urbanization, more and more non-renewable resources are exploited and accumulate in the urban areas as social material stocks. Mining these social stocks, on the one hand, provides secondary resources that can partially substitute for the primary resource supply and help slow down damage to ecosystems. On the other hand, they can generate environmental benefits. Furthermore, urban mining has become an industry offering economic benefits to the city. Urban mining is making its own contribution to sustainable development, but the research on the subject mostly focuses on the resource potential estimation, while a systematic UM theory remains under development. Practically, China’s government has acknowledged its benefits and put forward a specific national program to promote the UM industry and facilitate its upgrading to release a resource bottleneck in China. Will the social, economical and policy developments in China stimulate or restrict the sustainable development of urban mining? This is becoming a core question to be answered.

To achieve the objective, this doctoral study started by exploring the key attribute of urban mines, and the core issues associated with them. Together, these led to the formulation of a four-dimensional sustainable UM framework to serve as the theoretical background to this study. In the resource dimension, resource potential estimation and their substitution of the primary resource supply is the key issue. In the environmental dimension, positive and negative environmental benefits of UM are the key issue. A previous teamwork study the author was involved in explored the resource and environmental questions in China. It calculated copper (Cu), aluminum (Al), lead (Pb), and iron (Fe) metrics as these cover the four key metals UM potentials. It found that the stock of Cu is set to increase from 3.3 to 8.1 Mt, Fe from 223.5 to 711.6 Mt, Al from 9.3 to 37.0 Mt, and Pb from 5.5 to 12.1 Mt. By 2040, the substitution rate of Cu and Fe (UM supply over the primary supply) will achieve 25.4% and 59.9% and exceed the imported amount to become the main source of domestic supply. Urban mining of the four metals also generates substantial environmental benefits, in terms of the energy saving and reductions of water consumption, solid waste discharge, and Sulphur dioxide (SO2) emissions.

In the economic dimension, the key question is location optimization of the 50 national UM pilot bases the China government would like to support. Because urban mines generation are scattered given a wide range of demographic and economic factors, the location of UM facilities is and will be a key issue. A maximal covering location model combining a 0-1 integer programming method was constructed and applied on the ArcGIS platform. Results showed that 40 UM bases are sufficient to achieve maximum coverage of GDP and population. Considering an additional 50 Mt urban mines were imported to China annually, the decision of 50 national UM pilot bases by the government was reasonable. The government has already selected 28 bases with 22 ones to go. A second optimization process resulted in a list of 22 cities as the best candidates for these UM bases.

The key issue in the social dimension is the collection and integration of informal collection. The informal sector has already caused well-known environmental and social problems. Meanwhile, a new collection model had emerged in China with the assistance of ICTs and IOTs tools and, already, more than 50 private enterprises are now engaged in the intelligent collection. Intelligent collection in China takes two forms: Human-human interaction collection, and Human-machine interaction collection. Both forms apply barcode, sensor, GSM/GPRS and ICT tools. The intelligent collection has a good potential to integrate informal collection, as it has four comparative advantages. These include: 1) it is organized collection with legitimacy, 2) its material flow and cash flow is more efficient, 3) it harvests accurate and traceable big data, 4) it is a multi-source profit-making business model. In practice, the current intelligent collection companies in operation employ collectors from the informal sector. Considering the new social and economic trends in China, it is easy to foresee that intelligent collection can integrate the informal collection, not so easily in the short term, but might replace it in the long rum. UM management should make advanced planning of its strategy to apply intelligent collection in ways that can ensure a stable waste resource supply. 

This study further illustrated the four-dimensional issues in one UM city as a micro case study to explore how UM industry development in one city can impact its industrialization and urbanization and help contribute towards sustainable development. This study defined a UM city/town as one where the UM industry contributes the major economy and revenue to the city. Jieshou is a typical UM city. It is a microcosm of UM development across China and shares similar features with many other UM towns and cities. Driven by the population, cultural, and economic factors, Jieshou people took on UM recycling, and this has become a pillar industry in Jieshou. Metal recycling accounts for 80% of Jieshou’s industrial output value. Environmental and policy factors have acted as negative and positive feedback mechanisms and have further driven Jieshou to develop toward a circular economy city as its latest ambition. Jieshou’s experience includes: 1) establishing UM industrial parks for industry upgrading and collective pollution control, 2) taking advantage of national support policy to become a national pilot, and 3) providing direct guidance and subsidies to local UM technological innovation and integration.

Lastly, an in-depth policy assessment in China for UM brought the study back to the macro level, and its results can formulate specific policy advice for the core question of this thesis - sustainable UM development in China. UM policy in China was developed on the basis of a previous policy of circular economy and has now become an important pillar of the national circular economy policy schemes. UM development generally in China has sufficient policy support with the elements of national planning, legislation, and finance subsidy. But the governance of UM exists in a multi-ministerial cross-management network, and thus policy conflicts happen. Coordination between ministries and policy integration are needed to promote sustainable UM development.

The four-dimensional framework is an initial attempt; many more extensive issues remain to be explored in every dimension. This includes the simulation and visualization of the UM potential based on GIS platform, economic policy instrument designs for the efficient household recyclables resources collection, and many other collections system designs. This study constructs a theoretical four-dimension framework for sustainable UM analysis and strategy planning. Practically it provides specific policy advice for China government decision-making about the UM industry. The experience and lessons of China are also applicable for other developing counties, and for the EU counties with their circular economy targets.