So, how long will it be before our trash is more valuable than existing iron mines? The municipal waste collection system in the United States is very efficient at removing whatever materials we place in our trash bag. So much so, that we normally find it difficult to imagine the scale of the operation, and especially the scale of the mountain of material that is buried in our landfills each year. I wonder how long it will be before the sources of metals in our landfills is more valuable than our sources of metal ore.
According to the EPA, municipal waste collection systems gathered 230 million tons of waste in 1999, an increase from the 1996 value of 209 million tons. 28% of that waste, which comes from residential households and commercial buildings, was recycled, another 15% was burned, leaving 132 million tons for the landfills. I am going to assume that the amount of the annual increase in waste turned over to landfills has been reduced by 5% on an annual basis due to increased recycling and other efforts. The following figure illustrates the estimated current and historical amounts of landfill waste.
Studies of minicipal waste have found that by weight, 4% to 8% of the total waste is comprised of metals mostly steel and aluminum, but some copper and other things as well. The relative ratio of steel to aluminum depends on the geographical area and consumer trends, but each fluctuates between 25% to 75% of the total metal content by weight. [ad name="Adsense Small Horz Banner"] So, that means that during 2008 given our assumptions, we will likely put approximately 6.5 million tons of metals into our landfills using the lower limit for metals in our trash. Then, only counting waste collected since 1980, we could reasonably assume there to be a reserve of nearly 133 million tons of metals in our landfills. To produce a more accurate estimate of total reserves we could continue our calculation backward to 1945. If we assume zero metals placed in US landfills in 1945, and increase linearly to match our estimated waste in 1980, our grand total metal reserve comes to more than 182 million tons. Just for the sake of simplicity, I will assume that the total is one-half aluminum and one-half steel.
So, how does this compare to the metals and mining industry?
Well, by 1996, the United States was consuming approximately 100 million tons of steel per year, with a domestic production capacity along similar lines. Therefore, considering our "landfill reserves" of 91 to 182 million tons (depending on the actual portion of our waste that is in metals), we could not support the United States economy for long. So, it cannot be considered a vast resource, but it is still increasing.
However, if we don't try and replace all mining with landfll mining, there are other possibilities to consider in evaluating the feasibility of this venture.
Scrap steel prices are currently around $400 per ton making the lower end of just our steel landfill reserves valued at $36.5 billion, not a small sum. Iron ore, currently trades at a value of $1.40 per ton of ore rated at 1% iron content. But, remember, our landfill waste includes 2% to 4% steel by weight, making it much more iron-rich than native ore. The value of the landfill waste steel considered as ore should be approximately $12.8 to $25.6 billion, probably enough to supply a medium-sized company for many years of operations. Of course, the value of steel and iron ore continues to increase as global development continues.
Now, mining a landfill cannot be accomplished with standard mining equipment. Specialized tools will have to be designed, which costs money. Landfills range in size from small to large and are spread across the country, while iron mines tend to generally be large and concentrated in certain geographical areas. That makes landfill mining less attractive to someone looking to make a profit.
In conclusion, it seems that landfill mining may not be profitable for several more decades. But given the current trends, it will eventually prove a useful resource. On the other hand, more efficiently capturing metals prior to them being deposited in the landfill could be profitable as all of the material recovered would qualify as scrap and not ore. This type of program to recycle more of the materials thrown in the general rubbish bin, would likely be profitable today for corporations currently managing municipal waste systems even taking into account the increased captial devoted to sorting machines.