1.7a Mechanised Equipment

Introduction

The use of mechanised equipment has become increasingly popular in recent years. This section provides rudimentary practical advice on the potential application of different types of mechanised plant in path work within an upland environment and covers:

This advice is not a substitute for the knowledge and experience needed to be able to fully assess what can be achieved under varying terrain and conditions,which can only be gained through practical experience on the ground. There is however broad experience on hand amongst path managers, consultants and contractors who can give such advice, as well as skilled operators within the contracting industry who are capable of undertaking path work with plant to a very high standard.

AN EXPANDED CAPABILITY

The use of mechanised equipment as an aid to constructing, repairing and maintaining upland paths has expanded rapidly in recent years, and has become a key consideration for both client and contractor in planning, managing and implementing various types of upland path work. This change has stemmed from the availability of an expanding array of specialised lightweight yet robust, powerful equipment designed to do different path work tasks with limited adverse impacts. This has been coupled with a growth in the capability of upland path contractors who now own and are able to skilfully employ them to great effect

mini digger

Mini digger and power barrow

The successful application of these techniques in upland path work beyond the bounds of what was earlier thought possible has led in turn to a broader understanding and acceptance amongst path managers of the potential economic, logistic, environmental and safety advantages of mechanised plant as an aid to or in preference to handwork balanced with limited and acceptable levels of environmental impact.


PLANNING AHEAD WITH PLANT IN MIND

It cannot be overstressed that the time to think about whether plant might be applicable to a path work project is at the beginning, at the initial planning stage. Material excavation, transportation and handling is often the single greatest task in a path project along with path excavation and drainage and equally the dominant cost. For every metre of path to be repaired there could be anything up to a metric ton of materials to excavate, move out of the way and replace with either materials close by or at a distance. Multiply this by the length of path to be repaired and the scale of the task becomes apparent. Yet because these processes are masked by the end design and construction of the finished path, they are often overlooked, and is the key area where machinery excels.

Large excavator

Large excavator with long reach

The knowledge of how different equipment might be applied may fundamentally change the way a project is planned and executed, and the means by which path work materials are sourced, transported and used. At almost every stage in the construction process there are mechanical aids to reduce human effort, time and cost, and to perform tasks that would otherwise be impossible to achieve. These include;

Things to watch out for

A note of caution - don’t let the machinery take over! Once mechanised equipment is out on site, there is a natural temptation by all the parties involved to cut corners or undertake tasks that ought to be done by hand in order to save time, cost and effort. If not carefully managed, this can result in the design and finished appearance of the path being compromised as a function of the equipment dictating activities on the site. The standard by which the finished path will be judged, and the aim that all path managers should aspire to is that it should be very difficult to tell if the path has been constructed or repaired by machine or by hand.

Things to guard against include;

All plant operations need to be prescribed in the contract, and controlled through clear understanding between the client and contractor about how the path should look and feel at the end of the contract, and therefore what activities are acceptable. It also requires regular site visits to make sure these procedures are being adhered to.

Finally, in almost all cases mechanised operations will require varying degrees of “hand construction and finishing” to do the things which a machine cannot do and to help soften the appearance of the finished path to give it a natural and unobtrusive feel. It includes all of the obvious construction activities such as forming drainage features, revetments and stone pitching, but also includes softening hard lines and edges, grading surfaces, positioning edging boulders and turves and other important landscaping tasks. This requires a range of skills, not least of which is an aesthetic eye, attention to detail and a commitment to landscaping. This needs to be prescribed and costed into the contract and understood by all the parties involved. In some instances the main plant contractor may not be able to provide this service, and it may require bringing in additional hand skills to do it.

APPLICATIONS OF PLANT

Transport of plant and materials to the site

Function:
To transport plant and path work materials (eg earth, stone, gravel and turf ) to the site.
Method:
For larger jobs with robust site access (road access, hard surfaced tracks and strong bridges) it may be possible to transport plant and materials with a tipper lorry, tractor and trailer or dumper truck (single loads of between 1 and 20 metric tons). For short approaches to the site with sensitive terrain use a mechanised carrier, small tracked dumper truck or quad bike and trailer (single loads of up to 500kg). For long approaches to the site with difficult terrain and where ground tracking is unacceptable, materials should be carried as under slung loads by helicopter (single loads of between 900kg and 2000kg). The most common method of transporting plant is to track machinery onto the site by a pre-selected and agreed route. It is also possible to airlift small plant (or in extreme cases dismantle larger excavators into smaller loads) and airlift into the work site.
Troubleshooting/ things to consider:
Carefully evaluate location of materials needed on and off the site to reduce transportation distances and cost. Use on site materials wherever possible as this significantly reduces overall costs as well as potential impact to the approach route. Determine plant carrying capacity of terrain to and on the site. If ground access is appropriate, survey and agree line to be taken with contractor. Ensure permissions have been obtained from all owners of land that machinery will cross.
Transporting materials to site

Transporting materials to site.

Options:
There is a wide range and type of machinery for carrying materials, and all options should be carefully explored. Consider mix of transport methods to the site but avoid multiple handling of materials which is costly. Some small dumper trucks and carriers (400kg upwards) have a narrow track base that can be kept within the width of a surfaced approach path. In addition to flying materials to the work site, helicopters can be used to pre-position stone, gravel or other materials along the length of the path, thus reducing material handling and movement around the site. They can also be used to place surfacing materials directly into a prepared path tray with a hopper.

Movement of materials around the site

Transporting materials to site

Transporting materials to site.

Function:
To carry path work materials (eg earth, stone, gravel and turf) around the site and to stockpile or place them in position.
Method:
For sensitive sites with complex terrain it is likely that only a mechanised carrier, quad bike and trailer or small mini-digger will be appropriate. For less sensitive sites with easier terrain and where plant can be kept to harder ground, (e.g. in track restoration projects) it may be possible to use much larger machinery. Material movement should be reduced by careful site planning and in some instances prepositioning by helicopter or other aid (eg. winch). In the case of using a larger excavator and boom, there is sometimes no need to use a carrier as the reach of the machine can both excavate and deposit the material where needed in one operation.
Troubleshooting/ things to consider:
Operations should be carefully planned and agreed to reduce movement of plant across the site, and kept to the harder ground. In general plant should be worked from the furthest to the nearest point as the path is repaired, followed by any landscaping and hand finishing to eradicate plant tracking.
Options:
There is a wide range and type of machinery for carrying materials (400kg upwards), and all options should be carefully explored.

Drainage work (see Introduction to Drainage Techniques)

Function:
To cut and dig out path work materials from side ditches, drainage channels and cross drains.
Method:
Various sizes of mechanical excavator can be used with different profile and size of bucket for these operations. Extensive ditching excavations, particularly in forming low profile water channels is an operation where plant can achieve a result that would be too labour intensive and costly to achieve by hand. Won materials can be stock piled, landscaped or transferred directly to a mechanised carrier.
Troubleshooting/ things to consider:
Operations should be carefully planned and agreed to reduce movement of plant across the site, and kept to the harder ground. In an upland setting and particularly across wet open ground where drainage is needed, careful consideration should also be given to the visual impact of ditch excavations which may intrude on the landscape and spoil the appearance of the finished path. Whilst cutting a U shaped ditch may be more efficient and functional, in some instances it may be less intrusive and more in keeping with the surrounding landform to form a shallow trench lined with turves to act as a drainage channel. With careful positioning, profiling and finishing by a skilled operator, the result can be very effective and produce a drainage channel that will require far less maintenance in the long term. In general plant should be worked from the furthest to the nearest point as the path is repaired, followed by any landscaping and hand finishing to eradicate plant tracking. Ensure that drains are free from obstacles and no pooling of water occurs.
Options:
There are various sizes of mini excavator (0.9 to 1.5 tons), as well as medium and large excavator (2 to 15 tons) available. Shaped buckets designed to form drains to the exact measurements required can be used to good effect. Angling buckets can also be used to shape and form ditching.
Maintenance Tasks:
Drains should be checked regularly for any obstructions and cleaned out accordingly.

Excavation of materials

Function:
To win path work materials (eg earth, stone, gravel and turf), form, landscape and construct.
Method:
Various sizes of excavator can be used depending on quantities to be handled and any site restrictions imposed. For sensitive sites with complex terrain there are now a range of small but powerful mini-diggers available (0.9 to 1.5 tons). For less sensitive sites with easier terrain and where plant can be kept to harder ground, (e.g. in track restoration projects) it may be possible to use a larger excavator (2 to 15 tons). Methods must follow H&S guidelines that include depositing material a safe distance from the excavation and avoiding unstable sides. Earth, stone, gravels and turf can be dug by excavator and transferred to a mechanised carrier. In the case of larger machinery there is sometimes no need to use a carrier as the reach of the machine can both excavate and deposit the material where needed in one operation.
Troubleshooting/ things to consider:
There is often a trade off between the size and effectiveness of an excavator and its impact on the surrounding terrain. A large excavator may be more efficient and capable of handling larger loads but may cause more damage to the work site. Small mini excavators with retractable tracks (which can be spread out to improve stability) are now commonly employed for this work. The contractor should limit any path work excavations within what they can reasonably expect to take to a “weatherproof standard” within the day’s work. This is so that they don’t get caught out by unexpected weather conditions which could cause wash out of over extended excavations. Excavation is often made inefficient and more damaging by the mishandling of materials around the sides of the dug hole, and requires a skilled operator. A sensitive approach should be taken when handling soil and turf which should be laid on terram with turves laid soil side down to keep them in good condition.
Grading materials

Grading materials

Path construction and repair

Function:
To assist in the construction process by excavating the path tray, forming and laying path work materials.
Method:
Depending on restrictions relating to the site and the type of terrain, an excavator can perform many of the tasks needed to construct a path. It can be used to excavate the path tray and cross drains, cut turf to form the edges of the path, lift and lay stone in position, as well as grade, spread and roll surfacing materials. An alternative construction method, unique to the application of mechanised plant is the formation of “as dug paths”. This approach is dependant upon the suitability of naturally occurring materials within the substrate, the terrain and landform, and for these reasons has thus far been more commonly applied in a low ground setting. Within this operation the grading, spreading, turf cutting and landscaping is all carried out without the re-handling of any of the material. For more details see the Lowland Paths construction Manual, section 3.6.
Troubleshooting/ things to consider:
Care should be given as to the size and weight of machine used to minimise its impact on the site. Path design should take into account future access by machinery where appropriate for path maintenance and repair tasks. Once plant is on site, there is often a temptation to undertake or supplement all handwork tasks with these aids. Watch out that the use of equipment does not dictate the design or result in the finished work looking uniform in character. All machine work should be followed up on site to maintain a hand crafted finish.
Options:
There are various sizes of excavator that can be used as discussed earlier.

Track restoration

Function:
To assist in the restoration and reconstruction process, by excavating the surface of the old track, forming, laying and re-landscaping materials.
Method:
This type of work requires very large amounts of material to be moved and formed to eradicate the line of the track, and/or create a new path line and is therefore ideally suited to mechanised plant. Depending on the size of track to be restored, the terrain and site conditions, excavators from 3 to 15 tonnes are best suited. The reach of the machine will be one of the key factors that influence the decision on what size of machine is the most suitable for any given site.
Troubleshooting/ things to consider:
Care should be taken when handling soils and turf to maintain their integrity.

Re-vegetation (see section 4.5)

Function:
To assist in restoring eroded areas back to their original vegetated state.
Method:
Not the most obvious task for an excavator, but depending upon the size of the area to be restored it may be more efficient to spread soils by machine prior to seeding.
Troubleshooting/ things to consider:
Care should be taken when handling soils and turves to maintain their integrity, for example a deep root block is required for ‘leggy’ heather to survive.

PROJECT EVALUATION

The purpose of the table below is to help objectively evaluate whether mechanised plant is appropriate within the environment for the pathwork being considered, and to weigh up the practical and economic advantages that might be accrued. The aim is to provide a checklist so that all the different factors are properly considered.

Checklist Item Evaluation Yes/No
Planning stage
  • Has the specification been objectively assessed and designed to take advantage of mechanical aids where these are appropriate to the site?
  • Can the work be undertaken with machinery to the design standards required?
  • Can hand finishing be used to complete and enhance the mechanised plant operations on this site?
  • Have the cost benefits of using mechanised plant been properly assessed for all the different path work tasks?
  • Have all the options been evaluated?
Site sensitivity, natural & cultural heritage designation
  • Are there any restrictions on the use of mechanised plant (including the use of helicopters) imposed by site designation?
  • Have the landowner(s) and appropriate statutory bodies been consulted?
  • Has the local community and hill users been consulted about the proposed path work?
  • Have all the options been evaluated?
Access to and from the site
  • Is there an appropriate route to and from the site over which mechanised plant can travel?
  • Has this route been agreed in detail by both client and contractor?
  • Can the work be scheduled in the year when site conditions and access to it are more likely to be favourable?
  • Have landowner(s) permission(s) been obtained?
  • Should machinery be transported to the site by helicopter?
  • Have all the options been evaluated?
Site operation of plant
  • Do the path work operations lend themselves to be undertaken by mechanised plant?
  • Can plant be operated effectively, safely and with minimum environmental impact on the site? (i.e. has an assessment been made of the terrain, substrates, long and cross slopes and drainage)
  • Have all the different path work tasks been fully considered?
  • Should the work be limited to specific operations to limit wider environmental damage?
  • Have appropriate risk assessments been undertaken?
  • Has the storage and handling of fuel and oil been considered and a contingency made for any spillage?
  • Have all the options been evaluated?
  • Has the contractor taken full account of intended plant positioning to, on and from the site in their Health and Safety Plan?
Source/ excavation of materials
  • Do the quantities of materials required, site excavation or import to the site justify the environmental and economic case for mechanical assistance?
  • Can the right quality and quantity of materials needed be found on site from within the path tray and/or from adjacent ground?
  • Are there suitable borrow pit sites along or close t the length of the path to augment this?
  • Has any exploratory excavation been carried out along the length of the site to help determine this? Where else can suitable materials be found?
  • Has an appraisal been made following the above as to the form of path construction to be used, e.g. an aggregate/subsoil path as dug on site or through the import of materials?
  • Can these materials be efficiently excavated by machine and stored on site?
  • Have all the options been evaluated?
Movement of materials
  • Can mechanised plant be used to bring materials to the site and along the length of the site whilst limiting wider environmental damage?
  • Can machinery be operated effectively and safely within the damage zone?
  • Has an airlift of materials been considered?
  • Have all the options been evaluated?
Availability of skilled operators and plant
  • Are there suitably skilled pathwork contractors
  • with accredited qualifications and the necessary experience of the type of situation to operate the plant and undertake the work?
  • Is the type of equipment needed available from the contractor or can this be hired for the period required?
  • Are there suitably skilled contractors available at the time work is proposed?
  • Have all the options been evaluated?
Client and contractor
  • Has the nature of the work been clearly communicated and understood between the client and contractor?
  • Are the operations and restrictions on the use of plant fully understood?
  • Has the client fully explained this in the contract document and obtained a signed agreement by the contractor?
  • Have appropriate and effective working arrangements been made and agreed for site supervision and monitoring?

MANAGING PLANT

Specifying plant application in path work contracts

Control over plant operations

Training Operators

CONSTRUCTION AND DESIGN MANAGEMENT REGULATIONS 1994 (CDM)

Health and Safety

All H&S rules apply - even if out of sight in the middle of nowhere! Other H&S Regulations include – Lifting Operations and Lifting Equipment Regulations 1998 (LOLER), Provision and Use of Work Equipment Regulations (PUWER) and Personal Protective Equipment (PPE). Note the CDM regulations. Health & Safety File should include: