Environmentally considerate lubricants in mining

Frederic Farshchi explains how environmentally considerate lubricants can help to significantly reduce the impact of oil spillages in environmentally sensitive applications.

With established world coal reserves becoming more difficult to mine, supplies are increasingly originating from new sources.

At the same time, environmental issues are being brought to the forefront of global industrial activity across all sectors.

In common with a number of industries such as forestry, and construction, the coal mining industry operates equipment outdoors, and in these industries the use of environmentally considerate lubricants (ECLs) is becoming increasingly important as a result of tightening legislation.

A carefully planned and well implemented lubrication regime is an obvious starting point in protecting the environment from contamination by lubricant leaks and spillages.

Working closely in partnership with their customers, Shell Lubricants aims to ensure the correct lubricants are used in each application and a rigorous maintenance programme is put in place.

Using the wrong product or quantity can result in excessive leakage during operation, and an increased requirement for maintenance stoppages.

Maximising the period between routine maintenance and lubricant changes can also help reduce environmental contamination, as these operations can give rise to some unavoidable spills and leaks.

Avoiding lubricants entering the environment in the first place is the ideal scenario, but unfortunately, even in the most carefully planned and well managed operation, some amount of leakage is inevitable.

For example, hydraulic systems on mobile mining equipment usually operate at high pressures with exposed hoses, cylinders and seals.

As such, there is a high risk of hoses breaking and hydraulic fluid entering the environment.

Even a leak of one drop per second from a machine can give a cumulative fluid loss over a month of about 200 litres.

To ensure reduced environmental impact, companies can select from a range of lubricants which are environmentally considerate and have the ability to biodegrade into harmless, natural substances.

Biodegradability is the ability of a lubricant to be broken down by micro-organisms, such as bacteria and fungi, to simpler compounds.

The first stage is the loss of parent material, or "primary" biodegradation.

This is the alteration in the chemical structure of a substance, brought about by biological action, resulting in the loss of specific properties of that substance.

It does not mean that complete biodegradation has occurred, as the pollutant might still be present in different chemical forms.

Ultimate aerobic biodegradation is the level achieved when the test compound is totally utilised by micro-organisms, resulting in the production of harmless substances such as carbon dioxide, water, mineral salts and new microbial cells.

A substance which is "readily" biodegradable has passed certain specified screening tests for ultimate biodegradability.

A lubricant for use in an environmentally sensitive application should combine a number of important properties.

These include high biodegradability, which means it is rapidly removed from the environment by natural processes in the event of a leak or spill, and low ecotoxicity.

Ecotoxicity is the potential for a material to produce adverse effects in animals and plants.

The ecotoxicity implications of a lubricant are more complex and diverse than the biodegradability implications, and are usually dependent on the additive composition.

Also vital to the user is that the lubricant offers a well balanced technical performance to ensure reliability and efficiency.

In addition to coal mining, applications for ECLs include machinery operating in sectors such as forestry, agriculture, construction, railways, earth-moving, marine and water treatment.

In all these sectors, the consequences of a major spill could be serious, and inevitable routine leakages accumulate over time, with the potential to cause significant environmental damage.

Forestry is an example of an industrial sector which has recognised the potential environmental consequences of its activities.

Forestry companies consume vast quantities of oils and greases, many of which could affect the environment.

Looking at statistics from the French forestry industry, it becomes clear that ECLs can play a major role in environmental protection programmes on a global basis.

In France alone, the forestry companies use up to ten million litres of chain oil and three million litres of hydraulic fluid each year.

To work properly, chainsaw chains and bars must be adequately lubricated, with one chainsaw using around 3 litres of oil per day.

When a chainsaw is used, virtually all of the lubricant ends up in the environment.

Despite this, the use of mineral oil to lubricate chainsaws is still common practice in much of the world.

It has been estimated that chainsaw oil usage is approximately 8 to 11.5Ml per year in Germany, 4Ml per year in Sweden and 2Ml per year in New Zealand.

All the environmentally considerate lubricants produced by Shell are formulated using carefully selected unsaturated and saturated synthetic esters, or advanced technology rapeseed oil.

This prevents the problems of poor stability and loss of low temperature fluidity associated with historic products based on vegetable oil or low quality, unsaturated esters.

Optimised additive packages are used to give good extreme pressure and antiwear performance, corrosion protection and oxidative stability, whilst still maintaining environmental acceptability.

They can also match the performance of conventional lubricants, offering extended component life and reduced oil and fuel consumption.

Northern Europe was the first area to formally turn towards environmentally considerate lubricants.

Environmental concerns have led to environmentally considerate lubricants being made compulsory in Swedish and German forests, and in Austria two-stroke boat engines must use biodegradable fluids.

Each year in Europe, over 0.5Mt of lubricant is lost directly to the environment as a result of routine leaks and spillages.

For the USA, the figure is more like 1.5Mt.

Across all industrial sectors, spillage of mineral based products is becoming increasingly environmentally unacceptable and pressure to improve performance is coming from customers, environmental groups and regulators.

Companies that fail to recognise these pressures may find themselves at a significant competitive disadvantage.

Frederic Farshchi is Global Industrial Product Marketing Manager at Shell Lubricants.

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