February 29, 2008


Could Japan Be Rich in Resources? Exploiting the 'Urban Mine' Effectively

Keywords: Newsletter 

JFS Newsletter No.66 (February 2008)

Japan is generally regarded as a country with not many resources, particularly lacking in minerals and fossil fuels, and is considered dependant on imports for most of its supplies. Japan used to be capable of importing as many resources as necessary to sustain its industries, but the global resource situation is now changing rapidly.

One recent trend is that China, the biggest resource exporter, has started to restrict its resource export volumes due to increasing domestic demand from its surging economy. In addition to China, the resource demands of the other three BRIC countries - Brazil, Russia and India - are also rapidly rising as these countries emerge as economic powers. Resource demand trends in these countries are boosting resource prices around the world.

In this context, the concept of the "urban mine" is getting more attention. An "urban mine" sounds like a mine located in a city but these mines do not require digging into the ground - the urban mine is the stock of resources already existing in society. For example, iron bridges are regarded as a stock of iron. Mobile phones use various rare metals, and thus constitute a stock of resources.

Some metal resources are already collected and recycled from mill ends after manufacturing or from products discarded after use. For example, 18.36 billion aluminum cans, amounting to 298,641 tons in weight, were used for juice and beer in fiscal 2006. Of the weight consumed, 90.9 percent was recycled, and the ratio of recycled material used to manufacture new cans reached 62.1 percent.

In short, recycling aluminum cans several times over makes it possible to deliver drinks in these containers with less use of virgin aluminum. In the context of the urban mine concept, all aluminum cans in the society - including those now on the market and those in between uses - can be regarded as an "aluminum mine" in the cities. Likewise, scraps of iron, copper, aluminum, lead, etc are important material sources.

Growth in demand for the so-called rare metals and rare earths is particularly rapid, as they serve in a wide range of functions that support product innovation, for example in mobile phones and televisions. Since the stock of available resources on earth is limited, resource supply risk is rapidly expanding due to resource depletion and skyrocketing prices.

One possible way to reduce resource risk is effective use of the urban mine, that is, recycling scarce resources already existing in cities. However, the extent Japan's urban mine stock of these resources is presently unknown.

Komei Harada, chief of the material laboratory of the National Institute for Materials Science (NIMS) tried to determine the total amount of recyclable metals stocked in Japan. He calculated estimates for a wide range of metals: gold, silver, copper, iron, tin, zinc, lead, aluminum, nickel, antimony, cobalt, indium, lithium, molybdenum, platinum, tantalum, tungsten, and vanadium. The results of his study, announced in January 2008, revealed the scale of the urban mine in Japan.

These calculations were based on foreign trade statistics, or records of exports and imports, but Harada also used input-output tables because raw materials are often traded after being made into components or products. First of all, using the input-output table, he estimated the percentage of raw materials exported from Japan in the form of parts and products. Then, after multiplying the percentages by component demand determined from industrial statistics, he deducted the amount of raw materials that were exported as finished products. With respect to the volume of the iron stockpile, Japan's ferrous raw materials association calculated the domestic stockpile by using data on material flows in 2003. The results of Harada's calculation were almost coincident with the 2003 figures calculated by this association. This indicated that using input-output tables is a credible way to calculate the stockpile of each metal.

Harada's calculations revealed that the scale of the urban mine in Japan can compare with the stocks held by the world's leading mineral resource-rich countries. The amount of gold stockpiled in Japan is about 6,800 tons, which accounts for 16 percent of the world's current reserves of 42,000 tons. Its silver stocks amount to about 60,000 tons, accounting for 22 percent of the world's stocks. As these metals are used extensively in electronic parts, demand for them will increase and the supply is expected to be in crisis worldwide.

Japan's stock of indium, which is used in the form of transparent electrodes for display devices and solar power generators, equals 61 percent of world stocks. Moreover, Harada's calculations revealed that Japan's stock of many other metals amount to over 10 percent of world's reserves, such as tin (used for electronic parts) at 11 percent and tantalum at 10 percent.

In order to understand the scale of the urban mine in Japan, Harada also tried to calculate how many years the stocks will last if current global demands for metals are supplied only by Japan's urban mine. In these calculations, he found that Japan has accumulated as much as the entire volume of metals consumed in the entire world for two to three years. In particular, its stockpiles of lithium, expected to be in demand as a material for batteries, and platinum, essential as a catalyst and for electrodes in fuel cells, are large enough to meet total world demand for six to eight years.

Compared with the reserves at natural mines in major mineral-producing countries, Japan's urban mine has the largest quantity of gold, silver, lead and indium in the world, the second largest quantity of copper, and the third largest quantities of platinum and tantalum. It has often been said that Japan has few natural resources and Japanese people have believed this without question. However, the latest research shows that Japan has one of the world's largest stockpiles of rare metals.

The importance of the urban mine has not been recognized sufficiently in Japan, and systems to recover and recycle most of these rare metals have not yet been set up. Thus, Japan's urban mine remains undeveloped, and worse yet, quite a lot of these metals end up overseas in the form of low-priced scrap. Japan, and the whole world, need to use these urban mine resources more actively and efficiently.

For this to happen, collecting systems of used products and recycling facilities need to be set up. Japan's nonferrous metal industries recover nonferrous metals from waste such as discarded electronic devices and vehicles by applying separation and refining technologies that originated in the ore smelting process. Thus, to a certain extent, recycling facilities are already in place. In fact, a so-called "urban mine" has been set up where a real mine used to be: the Kosaka Smelting & Refining Co. (formerly the Kosaka Mine), in Kosaka Town, Akita Prefecture, has been recovering metals from electronic substrates using the huge smelting facilities belonging to the mine, which closed after 130 years of operations.

In this metal recycling process, about 280 grams of gold can be recovered from about 10,000 mobile phones, which weigh one ton. Considering that only five grams of gold are extracted from one ton of gold ore, it is obvious that the urban mine is an exceedingly rich resource. This phenomenon is not limited to gold. It is said that one mobile phone weighing 100 grams, contains 0.028 grams of gold, 0.189 grams of silver, 13.7 grams of copper, and 0.014 grams of palladium.

To take advantage of the urban mine, the collection rate of used products must inevitably be increased. For example, Japanese people tend to replace their mobile phones every 18 months on average. However, the collection rate of used phones is declining because an increasing number of users want to still keep their old phones for non-telephone functions - as an address book or camera - or for fear of leaking private information. Manufacturers also need to design easily disassembled products in order to make recycling collected used products easier.

A wide variety of natural resources are being exhausted around the world, exacerbating the risks of resource depletion and driving up prices for industries everywhere. Mitigating such problems will require the creation of systems for resource recovery and recycling that minimize wasteful use of natural resources and make full use of the rich resources that have accumulated in urban areas. These critical challenges for Japan and other countries of the world are just now taking shape. We hope to continue monitoring related events and report back in our newsletters.

(Written by Junko Edahiro)