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What’s geology got to do with it? 4 – Tennis!

What’s geology got to do with it? 4 – Tennis!

 As part of the ‘What’s geology got to do with it?’ series, Flo takes us on a tour of the links between geology and tennis! Warning: You may not want to read this if you have no interest in Geology OR tennis…. 

Now the disclaimer’s out of the way, I thought it was about time I married two of my greatest loves in life, Geology and Tennis. These two interests may seem completely at odds in terms of relevance, but as is the beauty with geology, it relates to just about everything!

So, summer in the northern hemisphere and therefore the two biggest Grand Slams in tennis are upon us!  The French Open, the king of the clay-court season is currently underway and Wimbledon, the jewel (and one of the few remaning…) grass court tennis tournaments is just around the corner.

But for a sport containing so few tangible objects: a court, a racket, a person and a tennis ball, how does it relate to Geology? Well….

Tennis Courts


Court Philippe Chatrier Court at the French Open, the only Grand Slam played on red clay. Source – Wikimedia Commons

Professional tennis is  played on 3 types of court surface, each with its own season during the tennis calendar.  You have the hard court season, which dominates most of the year between July and February, beloved by Djokovic, then you have the European and North and South American clay court season from February to May, favourite of clay-court extroadinaire Rafa Nadal and then the shortest season of all, the grass court season, occupying all of 4 weeks in the summer, from June-July, once dominated by Federer and recently by Murray! The most obvious link to geology here is the clay courts, so how do you go about building a clay court and what materials do you need?

Red Clay Courts

Well first of all, very few clay courts are actually made of natural clay. This is because they can take a very long time to dry out (which you’ll know if you’ve ever done any pottery….). For this reason, the red clay courts as seen at the French Open and numerous other clay court tournaments are actually made from crushed brick or shale. Bricks are used because they absorb water less easily than natural clay and are produced from a mix made from Alumina (clay), sand, lime and iron oxide before being fired until dry.



Guga Kuerten being awarded a cross-section of the court in his last match at the French Open in 2008. Source – Tennis Served Fresh Blog

So if you want to build a clay court like the famous red-clay courts of the French Open, first of all you need to lay a base layer, this is covered with a layer of crushed stones, this is then overlain by a layer of clinker. This is then followed by a layer of crushed limestone and finally, the crushed brick forms the thinnest layer at the top. A cross section of the layering under the court surface formed the trophy that former French Open champion Guga Kuerten received when he played his last match at the tournament in 2008!


You wouldn’t want the Philippe Chatrier court looking like this after a few hours of sunshine! Source – Wikimedia Commons.

Maintenance of the court after completion is a bit tricky as the clay needs to be constantly smoothed and watered in order to prevent dewatering cracks, a feature that many geologists are very familiar with!

Green Clay Courts

Maria Sharapova playing on the ‘green clay’ at the Family Circle Cup. Source – Wikimedia Commons

Not all tournaments use red clay, so called ‘green’ clay’ or ‘Har-Tru’ has become very popular in the United States. Har-Tru courts are similar in construction but are made from crushed basalt rather than brick meaning they are slightly harder and faster. According to their website, Har-Tru courts are made from ‘billion-year old Pre-Cambrian metabasalt found in the Blue Ridge Mountains of Virginia‘. This rock has two important properties, which is that it is hard and angular which allows it to ‘lock together to form a stable playing surface’ and the hardness provides ‘exceptional durability’.

Tennis rackets


A modern tennis racket with a carbon fiber-reinforced polymer frame. Source – Wikipedia Commons

As with many manufactured items, the raw materials required to make them eventually leads us back to our natural resources in the ground. Earlier tennis rackets were always made from wood, with strings made from gut, but these days, advancements in materials technology means that the majority of professional frames are made from ‘high modulus graphite and/or carbon fibre while titanium and tungsten are often added to give the frame more stiffness and the strings are made from nylon (although Federer and Sampras are famous for using natural gut strings).

Supplies of pure titanium are rare although titanium ores such as ilmenite and rutile are much more common. Titanium is largely mined in the titanium-rich sands of Florida and Virginia as well as Russia, Japan, Kazakhstan and other nations. Much more rare is Tungsten, which has seen a rapid rise in price in recent years as supplies dwindle. Tungsten has recently emerged as a ‘critical’ metal with the majority of the world’s tungsten supply located in China. However Hemerdon mine  in Devon which has been closed since 1944, is thought to host one of the largest tungsten and tin deposits in the world, and is set to reopen under control of an Australian firm in the near future with permit plans progressing this year.

For more on how a tennis racket is made:

Tennis Balls


Tennis ball advertisment, 19th century. Source – Wikimedia Commons

According to an article in the guardian published in 2013, manufacture of Slazenger tennis balls now has a 50,000 mile production journey before they end up in Centre Court at Wimbledon. Part of this journey includes the transport of various mineral resources. These include the transport of clay from the United States,  Petroleum Napthalene (derived from coal tar) from China, Sulphur from South Korea, Magnesium Carbonate from Japan, Silica from Greece and Zinc Oxide from Thailand. This exemplifies not just the truly global nature of the manufacturing markets but also the complex importing and exporting of many natural resources for something as simple as a tennis ball.

For more on how tennis balls are made, see the ITF website:


Tennis Net


Anatomy of a tennis net. Source – Do it tennis website.

The majority of the different parts of a tennis net are made up from either polyester or polyethylene, both formed synthetically. However, the raw materials required to synthesise both materials  started off as extracted hydrocarbons. Polyester synthesis requires the polymerisation of ethylene which is derived from petroleum.

60 million tonnes of polyethylene is manufactured each year and is the world’s most important plastic. It is made by several methods by addition polymerisation of ethene, which is principally produced by the cracking of ethane and propane, naptha and gas oil, all hydrocarbon fractions. In Brazil, a plant is being constructed to make polyethylene from sugar cane via bioethanol.


And that’s how geology underpins everything we know and love about tennis!


For more information on the link between sports and geology, see the United States Geological Survey’s article on ‘Minerals in Sports: Tennis’:

Policy Focus: 1 – Creating value from Waste

Waste and recycling is a growing issue in a world where abundant resources are diminishing. This week Flo Bullough looks at recent policy activity in the area of ‘valuing waste streams’ and the geo-relevant example of Rare Earth Elements.

This week, the House of Lords Science and Technology committee has been taking oral evidence on the topic of ‘Generating value from waste’ with a particular focus on the technology and processes used to

House of Lords Chamber. Source - Wikimedia Commons

House of Lords Chamber. Source – Wikimedia Commons

salvage raw materials from waste and what the government can do to encourage and assist progress in this area.

This topic was also discussed in a recent European Commission consultation on the Review of European Waste Management Targets and the Raw Material initiative which highlights the importance of recycling to ensure safe access to raw materials. Consultations like these seek to engage with experts in the relevant field and are useful research and fact-finding exercises to inform future government policy.

This is all part of a wider plan to try and incorporate the disposal and cost of waste into the manufacturing life cycle. Additionally, waste is not just a cost burden but can also be a source of valuable materials that can be recycled.  In 2009 Friends of the Earth published a report entitled Gone to Waste – The valuable resources that European countries bury and burn. This included data on the value of the waste we don’t recycle and the associated CO2 emissions. The report also attempted to calculate the monetary value of recyclables. They found that in the UK in 2004, the value of materials classified as ‘key recyclables’ that had been disposed of as waste,  was a minimum of £651 million (based on values for materials such as glass, paper, iron, steel and biowaste. Rare earth elements were not included in their study).


Landfill Site. Source – Wikimedia Commons.

Geo-Relevant Example – Rare Earth Elements


Internal view of an iPhone. Rare earth elements are used in the manufacture of electronics such as smart phones but when replaced often end up in landfill. Source – Wikimedia Commons

The concept of valuable waste is particularly true of the rare earth elements that end up in waste streams through discarded electronics. Demand for rare earth elements is soaring while scarcity and market cost is increasing. Rare earth elements are essential to many commonplace electronics such as mobile phones and computers as well as in renewable technology such as wind power. The supply of these materials is finite and the market is currently dominated by China (see this excellent post from Geology for Global Development on the issue) which has its own geopolitical implications and so increasing focus from both an environmental and economic perspective is to extract these valuable materials from waste streams.

In terms of current research into Rare Earth Element recycling, Japan is the only place where significant research is being undertaken. An example of this is Hitachi who are aiming to be able to recycle electric motor magnets. It was also announced last year that the US is to build a $120 million ‘Critical Materials’ institute in Iowa which will focus, amongst other things on developing recycling techniques.

For more information see the following links:

Chemistry World – Recycling rare earth elements using ionic liquids – Rare earths recycling on the rise

POST note from the Parliamentary Office of Science and Technology – Rare Earth Elements


What’s all the Phos about?

What’s all the Phos about?

Phosphate use for fertilisers, essential in modern agriculture, is hitting an all time high while resources are being heavily depleted. Flo discusses the background, numbers, geopolitics and potential solutions behind the issue of ‘the end of phosphorus’.

The Issue


Modern agriculture has developed in-line with the availability of high quality phosphate-rock fertilisers. Source – João Felipe C.S, Wikimedia Commons.

The dilemma over diminishing natural resources is a topic of our times with the daily bulletins filled with reports related to resource shortages. These mainly focus around water, energy and food which are imperative for human survival. Whilst energy and water are often debated in the media and political chamber, an area that gets much less attention is agriculture, and in particular diminishing phosphate resources used for industrial fertiliser. Modern agriculture, particularly in developed countries has used mined phosphate for fertilisers for decades but this finite resource is being depleted at an alarming rate.

A combination of growing population, aspirational lifestyles and the demand for phosphate-intensive meat and crops has caused the rapid reduction of phosphate rock resources. In the past, prior to the advent of phosphate mining, additional phosphate for farming and agriculture was sourced from manures

Prior to use of phosphate rock, it was replenished through the use of manure.

Prior to use of phosphate rock, it was replenished through the use of manure. Source – Malene Thysson, Wikimedia Commons.

and organic waste, but as agriculture intensified, the hunt for easier, more accessible phosphate began. From the mid-20th century onwards, the use of rock phosphate was used as a high quality, easily accessible sources of phosphorus which gave rise to the modern fertiliser industry as we see it today. Farmers in rich countries such as Europe and North America became hooked on the cheap and easy phosphorus which readjusted agriculture practices and set phosphate demand through the roof.


Phosphorus (P) is a non-metallic element which is almost always present in a maximally oxidised state (PO43-) as inorganic phosphate rocks due to its reactivity. Elemental phosphorus can exist as red and white (known for its use in weapons and artillery) phosphorus but almost never found as a free element in nature.

It is one of the building blocks of life and life simply wouldn’t exist without it.  It is a key component of DNA, RNA, ATP and phospholipids and is essential to cell development, reproduction and in animals, bone development. The use of phosphorus compounds in fertilisers is due to the need to replace the phosphorus that plants remove from the soil.There is no substitute for this element. Supplies are limited and much is currently wasted, creating concerns about future supplies in the EU and worldwide.

Peak Phosphorus?


A graph of world phosphate rock production vs. year from 1900-2009 obtained from the U.S. Geological Survey. Source – Thomas D. Kelly and Grecia R. Matos, Wikimedia Commons.

Recently there has been a proliferation of articles and discussion over the potential for ‘peak phosphorus’ in the next 20-30 years. World production recently peaked at <160 million metric tonnes (mmt) in 2008. Whilst the majority of people agree that phosphorus is a resource that is of concern, not everyone agrees with the peak phosphorus hypothesis or its potential timing.  Proponents of the argument include this group of academics who published a paper entitled ‘The story of phosphorus: Global food security and food for thought’ and Jeremy Grantham, co-founder of the investment firm Grantham, Mayo, Van Otterloo, who recently wrote a piece in Nature. On mined-phosphate fertilisers, Jeremy Grantham stated that ‘There seems to be only one conclusion: their use must be drastically reduced in the next 20–40 years or we will begin to starve’. Much of the peak phosphorus argument comes from a widely produced diagram from a 2009  paper in Global Environmental Change depicting peak phosphorus to be around 2030 followed by production declining at an accelerating rate.  Detractors to this theory say that the markets are likely to adjust to this problem and cause the price to rise thus forcing a reduction in use and a push for technology to advance to find new sources or recycle current phosphate use. The International Fertiliser Development Center (IFDC), through extensive data gathering state that there is “no indication that a “peak phosphorus” event will occur” in the next 20-25 years.

Resources and Geopolitics


Phosphate mine near Flaming Gorge, Utah. The large size of phosphate mines is dictated by the dispersed nature of phosphate in the rock. Source – Jason Parker-Burlingham, Wikimedia Commons.

Phosphate rock is typically mined at high volume due to its dispersed nature in the rock. Phosphate, in the mineral form of apatite in phosphate rock, is not bioavailable to plants and must be processed to convert it to a plant-available form. The concentrate is used to produce phosphoric acid which is then used in fertiliser products.  Phosphate rock can come in either a sedimentary or igneous form, with sedimentary making up >80% of total global production.


Topographic map of Western Sahara. Western Sahara is disputed territory but is currently controlled by Morocco and therefore the Moroccan Royal Family. Source – Sadalmelik, Wikimedia Commons

In addition to the concern over the amount of resources and rate of use, also of concern is the location of much of the world’s supplies. Europe in particular has scant phosphate resources with a small amount in Finland.   According to the IFDC report from 2010, 72.1% of the world’s phosphate rock production was accounted for by China ( 31.5%), U.S.A (18.7%), Morocco and Western Sahara (15.5%) and Russia (6.4%). However a significant proportion of the world’s high-grade supplies are located in the disputed territory of Western Sahara in North-West Africa, currently controlled by Morocco. This has been termed by Jeremy Grantham  as ‘the most important quasi-monopoloy in economic history’.

Country Mine Production 2007
Mine Production 2008
Reserves Reserve Base (estimated)
China 45,700 50,000 4,100,000 10,000,000
Morocco and Western Sahara 27,000 28,000 5,700,000 21,000,000
Russia 11,000 11,000 200,000 1,000,000
United States 29,700 30,900 1,200,000 3,400,000
World Total (rounded) 156,000 167,000 15,000,000 47,000,000

Table adapted from USGS Mineral Commodity Summaries January 2009. Data is presented in thousand metric tonnes.

Phosphate rock resources in Western Sahara are extremely large and still incompletely explored and therefore it is not understood if the rock is producible at current prices and costs as there is little to no data. The IFDC estimates global resources of 290,000 mmt but if Morocco and Western Sahara resources are included (340,000 mmt) it may increase to 470,000 mmt, as seen in the above table.

Environmental Impacts


Eutrophication in a pond in Lille, France. Eutrophication is caused by the enrichment of an ecosystem with chemical nutrients such as phosphorus. Source – F. lamiot, Wikimedia Commons.

The use and mining of phosphorus also carries risks. In agricultural use not all of the phosphorus is absorbed by crops which results in leaching into the water. This causes the much discussed eutrophication effect causing algal blooms. Phosphorus mining is also difficult environmentally as it generates a large amount of the waste product phosphogypsum which contains both toxic heavy metals and low levels of radiation. This is very difficult to dispose of and often results in mounds of unprocessed waste material.

As lower-cost phosphate resources will be mined out, mining companies will utilise lower grade ores which will incur the use of more energy and water and will cause the price to go up. Availability of water is of high importance to mining operations and indeed this can dictate the feasibility of phosphate extraction, areas of low water availability may completely restrict development of the mine. Another way in which water, energy and food are interconnected.

What next?


Wastewater discharge pipe – New studies show useable phosphorus can be recovered from wastewater. Source – Department of Agriculture, Wikimedia Commons.

Regardless of the proximity of ‘the end of phosphorus’ it is very much a finite resource and thus development towards more effective use and recycling needs to take place.  Recently, the Environment section of the EC launched a consultation into how to use phosphorus in a more sustainable way, following on from a conference held in March on Sustainable Phosphorus. They have also posted a series of informative videos that can be found here. Much work has been done on the ways in which we can curb our phosphate use or recycle it more effectively. More must be done to monitor and reduce phosphate use as well as recycle wasted phosphate. A few of the potential solutions are listed below.

Phosphate reduction

  • Changes in people’s daily diet away from phosphorus-intensive foodstuffs such as meat. 
  • Since much of phosphorus is lost from the food cycle through waste, a reduction of food waste and its reuse in composts etc could reduce demand.
  • Current agricultural practices result in a very high use of fertilisers. A switch to techniques and practices that conserve more soil nutrients would go some way to reduce phosphorus waste. This includes organic agriculture and use of permaculture (sustainable and self-sufficient agricultural practices).
  • Genetic engineering could produce plants that can flourish with much lower phosphorus use.


  • We can recover useable phosphorus from waste streams including urban sewage, since current systems already remove phosphorus from sewage to preserve water quality. Wastewater carries a lot of struvite, a mixture of ammonium, magnesium and phosphate which builds up in the pipework.
  •  A team of canadian researchers believe struvite can be turned into environmental friendly fertiliser, as discussed in this national geographic article. Together with the local government they have set up a lab next to a waste water treatment plant. This process works by altering the pH and allows the wastewater chemical to bond together into pellets through a turbulence process. Currently a working prototype can turn out several tons of pellets a month. Since 2010, the technology has been incorporated into 5 waste water facilities in North America. Whilst there are some cost issues to address, there is relatively little further work required to reproduce this technology on a wide scale. Higher phosphate prices would push wastewater recovery to be economic.