An archaeological dig like no other

As Costain-Skanska JV’s lead archaeologist and project manager for HS2’s St James’s Gardens excavation in Euston, Caroline Raynor explains how she united a diverse project team using borrowed Lean principles with great success.

Great Britain is a small island with a long history and a lot of stories to tell. People have been walking, settling and adapting the landscape to meet their needs for a very long time, and in doing so have left a plethora of evidence about what they were doing and what they did it with. If you work within the construction sector in the UK, it is highly likely that you will have to deal with the management of the archaeological ‘known unknown’ and, by proxy, large teams of archaeologists. The larger the project, the greater the potential there is for uncovering an archaeological site along the way.

The relationship between archaeology and construction has often been a challenging one. This is in part because archaeology is the ‘known unknown’, and the fact that it is not easy to quantify, measure, programme or package up can present difficulties, particularly where there is no shared common language between project managers, construction site teams and archaeological contractors and their specialist staff.

Archaeological project management is often delivered in line with guidance produced by Historic England. The guidance, known as MoRPHE (Management of Research Projects in the Historic Environment) was published in 2015 and deals with the project life cycle, planning techniques and documentation associated with historic environment research projects (download it for free at www.historicengland.org.uk).

Different perspectives but common goals

Despite differing approaches, the goals of project delivery are one and the same for archaeology, heritage and construction: to deliver a high-quality product safely, on time and to budget; to delight your clients; and to leave a lasting legacy. Achieving these goals has been key for the way archaeology and heritage activities are managed on HS2 enabling works.

HS2 is the largest, and arguably most complex, infrastructure project currently underway in Europe. A huge amount of work has already been completed to facilitate the construction of the new high-speed route, which will provide an additional link between Birmingham and London. A key focus of the enabling works activity has been archaeological excavation, built heritage, research and engagement. HS2 project requirements for managing and delivering historic environment works are set out in a series of technical standards and the Historic Environment Research Delivery Strategy.

Placing archaeology and archaeological practice at the front and centre of early works is shaping a new generation of project managers and archaeologists, encouraging new and innovative approaches, and opening new pathways for dialogue between construction teams, historic environment specialists and governing bodies such as Historic England and the Chartered Institute for Archaeologists.

Working for Costain-Skanska JV on the enabling works in Area South, our archaeology and heritage work takes on myriad forms. From the recording, dismantling and relocation of Grade II funerary monuments and famous public art and sculpture, to the archaeological excavation of sites dating from the Mesolithic to the post-medieval period, we are working to understand a time scale that spans more than 11,000 years.

Geographically, our remit spans from Euston station to the Colne Valley, north-west of London – approximately 25km of route under archaeological investigation, with hundreds of experts busily recording, measuring, 3D-modelling, excavating and conserving everything that we find.

Uncovering St James’s burial ground…

Directly to the west of Euston station, within the proposed development footprint, lies the former site of St James’s Gardens, a post-medieval burial ground whose register indicates it was the resting place of around 60,000 individuals, interred between 1789 and 1853, when the Metropolitan Burials Act was implemented and the site was closed for burials.

Deadly diseases, including a number of cholera epidemics, in the early to mid-19th century generated a drive towards public health led by Sir Edwin Chadwick, which resulted in the passing of the Public Health Act in 1848. This awarded powers to local councils, which were then able to regulate urban areas, providing services such as street cleaning and management of night soil (open middens in courts and alleys), and ensure a clean water supply.

Epidemics (and pandemics), as we are well aware today, take their toll on public services, not least of all on burial grounds. Sir Edwin was undertaking a portfolio of national projects on a whole new scale. As a result of this work, burial grounds were flagged as a problematic area and, in 1853, the Metropolitan Burials Act was passed, prohibiting burials in built-up inner-city areas.

St James’s burial ground has been subject to archaeological excavation and investigation on a scale that is quite unparalleled, with over 200 engineers, archaeologists, surveyors, drone pilots, construction operatives and specialist services coming together to work as a team. Unusually, the methods, efficiencies and innovations have been led by the construction team. The team were united around the core values of care, dignity and respect for those interred within the burial ground.

This has been one of the main focal points of work and will form a major part of a BBC television documentary this autumn. To us, this is our ‘biggest dig’ and is arguably part of the largest programme of archaeological works currently being undertaken in Europe.

…then covering it back up again

Archaeological excavation of the burial ground has proven to be one of the most exceptionally challenging and rewarding activities. Working on a site that exceeds all known parallels in terms of scope and size provides the opportunity to look at archaeological processes and project management in an entirely new light, including applying new methods, digital techniques and Lean practices to help make changes in the industry.

One of the first opportunities we identified was the potential to enclose the whole site of the archaeological dig. By enclosing the site (effectively building a very big tent), we were able to discharge our requirements to our stakeholders (the historic environment works have 52 of them) by protecting and ensuring the care, dignity and respect of all those interred within the site, as well as weather-proofing the works and providing a safe working environment for the 200-strong team.

The encapsulation structure was built using system scaffold and the twin-apex roof was supported on 15 bespoke prefabricated steel towers. The structure spanned 110m x 90m and, with additional outriggers, enclosed an area of over 11,000m2. Constructing the tower foundations and footings required 15 separate mini-archaeological excavations. Volumetric calculations indicated that burial horizon (depth of the burial ground) might exceed 6.2m below ground level, and we determined that the foundations of the structure needed to sit below the formation level of the dig to ensure we were never going to undermine our own temporary tent.

Going underground

During the sinking of shafts and excavation of the burials to install the footings, we were amazed to find that burials exceeded depths of 7.3m, making the site one of the most deeply dug post-medieval burial grounds in London and posing additional engineering challenges. Even the archaeological team had to be specially trained for working in confined spaces in order to complete this activity. This part of the work also gave us pause to consider the Georgian and Victorian grave-diggers who would have originally dug these graves into the stiff London clay. Hand-digging vertical shafts over 7m through consolidated London clay is no mean feat.

This early part of the project provided us with our first real detailed view into the cemetery and the difference in levels of preservation in the upper, middle, lower and pauper’s ground. It very quickly became apparent that perched water in the ground, combined with the London clays, had created a perfect storm of anaerobic conditions. This has led to unprecedented levels of preservation of artefacts, including personal objects associated with burials (jewellery, coins, floral tributes and even a pair of beautifully decorated hand-made Indian slippers), and decorative metals known as ‘coffin furniture’.

One of the truly incredible things about managing an archaeological site full of experts is the way that it changes daily as progress is made and the history of the site gradually reveals itself under the careful hands of the archaeologists and osteologists. Every day brings new learning and the shared joy of new discoveries. Being the first person to see an artefact under excavation is a unique experience that is quite difficult to articulate, but it makes managing and delivering the works all the more rewarding.

Borrowing Lean principles

Inside the encapsulation structure, the ‘big dig’ was a highly choreographed hive of activity, with carefully managed interfaces between specialist disciplines. One of the main challenges was achieving a tight programme, and we turned to Lean principles to provide answers. Lean is a tool traditionally associated with production lines and business management; however, it can have successful applications across a large number of archaeological activities.

Lean originated in the car manufacturing industry and built upon Henry Ford’s moving assembly line for mass production. Toyota advanced and evolved the concept in the 1960s by seeking to identify waste and eradicate it, whether it be cost, time or effort. Encouraging and supporting people to develop Lean skill sets has been a key part of delivering efficiencies in archaeology and providing a clear set of data that can be interrogated to understand productivity.

Archaeology is not a production line and no two archaeological sites are the same. But archaeology as a discipline is process-driven, and activities such as finds-processing or excavating a feature or burial are governed by rigid methodologies that make archaeology an entirely suitable discipline in which to trial Lean controls and processes.

The most common wastes in archaeology are the waste of motion (such as walking across site seeking tools and equipment); the waste of transport (moving samples and finds from site to office without checking labelling, volumes etc); the waste of waiting (delays on-site caused by weather or lack of plant, leading to the inefficient use of time on-site when secondary activities could have been planned); and the waste of talent (not understanding or registering the key skills present among an often transient or temporary archaeological workforce). High-level analysis indicated that waste of motion, transport and waiting occurred most frequently on other sites, and these were elements we sought to eradicate.

Something to lean on

Measures were put in place to help reduce or remove waste, and the improvements were measured using a Lean control board where ‘time on task’ and the metres-cubed of material removed were recorded each day as a productivity measure. Productivity initiatives included the use of small all-electric plant (1.9-tonne mini-diggers and one-tonne tracked barrows), digital recording and the deployment of one site operative per five archaeologists to help with spoil management and muck shift.

The use of a bespoke Lean control-board proved to be a great boon, as it provided a clear way of communicating, collating and interrogating data. Conversations could be open and honest, as they were based around factual data.

The huge volume of finds and artefacts required special treatment, and Lean was applied to this suite of activities too. Finds management activities were also process-mapped to identify opportunities for efficiency, and a bespoke laboratory with a factory production line approach was built on-site. This facility considered specific tasks, optimal production (task time) and ergonomics based on a 43 per cent female demographic on-site – a rarity in most construction environments. Additional benefits were also identified where on-site processing provided earlier insight into the assemblage and helped to inform excavation and community-engagement strategy over the duration of the project.

Large archaeological projects of this kind will become more common as the scale of UK infrastructure projects grows. A key piece of learning has been to develop an integrated specialist team with a shared common language and values, who can work together to support and drive innovation.

A diverse dig

With a 43 per cent female demographic on-site, the St James’s Gardens excavation is a rarity in most construction environments. A proactive approach was taken to encourage and seek out female engineers, “although, ultimately, I must always select the right person for the right role, regardless of gender”, Raynor reiterates. The archaeological team is generally quite well balanced in terms of gender, she says, with roughly a 45 per cent female to 55 per cent male split. “However, the win was setting up an environment suitable for women to work in that helped eradicate common issues and eliminate staff attrition, sickness leave and occupational health issues such as musculoskeletal issues and minor injuries,” she says. Female roles on-site in the construction team included project manager, lead archaeologist, apprentice engineer, section engineer and sub agent, while roles on the archaeology team included project officer, supervisor, field archaeologist, surveyor and osteologist.