The hidden risks the ground poses to farmers and landowners

Land. A word that is defined by its ownership, purpose, value or location and is often viewed, from a local, regional or national economic perspective, for its agricultural or development potential. However, land in the UK is also defined by our geological and extraction history, both of which can pose significant risks to property, investment and people. 

Image copyright of Terrafirma (2017)

Image copyright of Terrafirma (2017)

Naturally, the larger the area of land, the more varied the geological conditions and therefore, potentially, the greater the risks posed. Geohazards can take many forms including stability of a slope, erosion of rivers or cliffs, natural subsidence, ‘sinkholes’ from natural voids or caves or, perhaps most importantly, sub-surface, man-made structures. These are commonly linked to mineral extraction, but can also be from war-time infrastructure, Victorian era sewers, wells and even smugglers’ tunnels. The subsequent abandonment of these structures over a century ago, combined with a continuous deterioration of condition, lack of records and an increasing occurrence of heavy rainfall events means a risk of collapse or subsidence is ever-present until identified and managed. 

According to survey information collected by Cornish Mutual there are growing health and safety concerns from public rights of way within the UK farming community and it is clear that the law surrounding the rights and liability of the land owner when it comes to the public needs urgent clarification. When owning, leasing or working on large areas of land, it is essential to understand the risks that may be present and how they may affect your liability or the safety of others. An often-overlooked fact of owning land is the ‘Inheritance of risk’ that comes with purchasing or having land passed down through generations and this is particularly prominent in environmental hazards, such as ground instability, flood, contaminated land and invasive species. Understanding the risks that are or are not present can provide greater clarity over the potential purpose or management of the land and help influence its use, sale or value. 

The risks the ground poses are variable and widespread across the UK and controlled predominately by local geology, topography, level of water table and the historical ownership of land and its use. Data to understand environmental risks has until recently been poor in accuracy and relevance, however, significant steps have now been undertaken to ensure that assets are secure and the public are safe, as the visibility and frequency of environmental hazards increases. Historical mineral extraction is one such hazard, commonly perceived to affect a number of areas across the UK Cornwall however, in reality, there have been over 60 minerals quarried and mined from beneath our nation’s surface, dating as far back as 5000 years ago. 

Mineral extraction occurs in every corner of every county in the UK, with ancient mine shafts and shallow underground workings littering our landscape, often lost and forgotten beneath agricultural land, suburbia and emerging industrial and property developments. The older workings (pre-19th Century) are usually located within, or beneath, agricultural land and there are numerous examples across the UK. The extraction of minerals is controlled by demand and in ancient times, metals such as tin, iron, lead, silver, gold and copper were sought after and prevalent across large areas of the UK. Mineral resources were at first exploited at the surface and followed underground, dependent on value and demand, therefore making the oldest workings the shallowest and consequently posing the greatest risk to ground instability. There are a growing number of mining-related ‘sinkholes’ each year, including 48 notable collapses in just the last 12 months, many of which occurred in rural areas and within agricultural land. 

A ground collapse in East Harptree, North Somerset that occurred earlier this year has been attributed to a combination of ancient lead mining and natural karst (cave) systems, has highlighted the very real risks the ground poses to land owners across the UK. In February 2017, emergency services were called to help free a horse from a ‘sinkhole’ that occurred in a field leased out by the landowner to store horses, however, the field also had a public right of way that passed directly adjacent to the ground collapse. Questions were quickly and justifiably raised as to what the liability is regarding ground collapse and public safety on rights of way and a full professional geological risk assessment was commissioned to ensure that the land owner was complying with a duty of care to ensure the land is as free as possible from all obvious hazards. 

Many parts of the UK are understood to have had a long legacy of mineral extraction. Land in Somerset, the Peak District, North Wales and Cumbria has been exploited for lead/zinc and other metals with many tens of thousands of mine entries recorded across these regions. In the Peak District alone, there are over 1000 known mines with an average of between 3 and 5 shafts or adits per mine! Other minerals, such as limestone, iron, chalk, evaporites and more obscure commodities such as Jet, Fuller’s Earth and Flint have all been extensively mined across the UK, often in predominantly rural areas, posing a localised but potent risk to landowners. Unlike in coal mining areas where The Coal Authority has an obligation to remediate, the responsibility and risk of any ground deterioration and collapse in these mining areas is inherited by the land owner upon purchase and these hazards may be to the detriment of the value and purpose of the site, possibly leading to damage of the environment or endangerment of public health and safety. 

There are numerous methods of reducing land owner liability, such as liaising with the local council to divert rights of way, appropriate signage and comprehensive public liability insurance, but without a better understanding and perception of your land, it is not possible to have ensured these mitigating processes are undertaken. Owning land often inevitably means owning geohazards and to ensure reduced liability, value, purpose and public safety, it is now essential to know your land and accurately identify, professionally manage and comprehensively mitigate the risks the ground poses.

Authored by: 

Tom Backhouse, Managing Director of Terrafirma.