Webinar on 'Minerals extraction and Archaeology'

Minerals Extraction and Archaeology 

Speakers: Duncan McCallum, Guy Robinson, Jane Corcoran, Sandy Kidd and Sasha Chapman 

Duncan [00:00] Duncan McCallum, director of strategy and listing at Historic England, and welcome to this webinar on mineral extraction and archaeology. It's great to see so many people in the room – up to 90 now, I think – and we've got four expert speakers for us in this next hour. So as many of you know, this webinar is closely connected to the Historic England advice note on minerals extraction and archaeology published early last year. The advice note was a long time in development, and this webinar has taken us a while to come to fruition, but we're delighted to be here, finally. 

Several years ago, it was the shared hopes of Historic England, heritage sector partners and the minerals industry to produce a document that we could all sign up to. Many discussions took place over several years within the minerals and historic environment forum, and we were very grateful for all the hours, input and patience from all those partners. 

There's a lot on which we agreed and that's reflected in many ways in the content of much of the advice notes. However, the advice note is published under our banner, Historic England banner, alone, and as a result, this webinar is delivered by Historic England staff. So discussions on key topics most notably evaluation, trenching, continue. And we are supporting further research that might inform a revised iteration of the advice note in future. 

I'll return at the end of the four short presentations and take a few questions for the speakers. But without any further preamble, I'll pass over to Guy Robinson, who's a policy advisor in the National Strategy team. He'll begin the main content of today's session, which I hope you'll find very useful. Take it away, Guy. 

Guy [01:50] Thank you, Duncan, and good afternoon, everyone. I will begin with some brief introductory remarks before passing the baton to Jane Corcoran, to explore archaeological interest, and then Sandy Kidd, who will focus in more detail on assessing archaeological potential of a site within the development management process. And that broadly echoes the structure of the advice note for those who have already had a look, or do have a look, if you haven't already, and I've put the link in the chat. Sasha Chapman will then round up the webinar with some case study content, and hopefully, there will be still time for questions. There's a lot in the agenda, so let's crack on. 

First question for you all, please. Let's see who's joining today. Please, if you can answer the following question if Rachel can put that on the screen – just give a sense of who's in the room. Thank you. The results are coming in. I guess everyone who has answered who's going to. Thank you. That's really interesting. Clearly, we can see a large number of archaeologists in the room, which is wonderful. But on that, I suppose we may be covering some ground that I'm sure you may know already, but also, it's quite a mixed audience, and hopefully, in this content here, there'll be something in here for all. And there's always the chat room, as Rachel has already mentioned, to raise issues and questions. 

OK, so I'm going to head on to my little introduction. Perhaps worth beginning by stating the age-old mantra that minerals can only be extracted where they occur. Mineral development occurs on a wide variety of geologies and within wildly contrasting landscapes settings. Archaeological remains vary from region to region, and it's not surprising that they can be found in different types of quarry as a result. And here in this slide, we've got a picture of a sand and gravel quarry in Essex, top left, a building stone quarry in Somerset on the right-hand side, which will be covered in more detail in the case study content from Sasha, and a limestone aggregate quarry in Derbyshire, bottom left. 

So in the advice note, we tried to highlight the different archaeological techniques that can be employed. Alongside flagging some more key elements, shall we say, of a more consistent approach in predetermination evaluation, which includes having a high-quality desk-based assessment and considering the full suite, the full range, of archaeological techniques when approaching the site and taking a question-led approach to evaluation. This box, incidentally, is just snipped from the advice note itself, and I think there are other speakers today who have done something similar, so if you see a slightly green-shaded box, that's just an extract from the advice note. And I realise that this is leaping into a good deal of detail early on, so I'm just going to step back, but I just flagged that as an initial thought and part of the thinking in our approach to preparing the advice note. 

So coming back to why, a question I often ask myself. Why is the advice note needed? Why did we start work on this project? Well, undoubtedly, there are some considerations that are common to other types of land use, but quarries can be more destructive to archaeological remains than many other types of development-lead projects. And at the same time, mineral extraction can also provide special opportunities to deliver new knowledge. In particular, I'm thinking about wide-scale information, so linked with landscape archaeology, and also Palaeolithic evidence about our distant past. 

So we then sought to tease out some of those particular individual issues in the advice note, which I hope is proving helpful. It's, as I say, published about a year ago now. One of the early elements in the introduction we focus on is plan making, and if I just touch on that for a minute. As you all know, dialogue is vital at all stages of the planning process, beginning with plan making, and considerations of new sites or areas for development, and this brings with it the need for heritage assessment, and that would inform allocations, certain site allocations, and also, when considering areas of search or preferred areas, at which point detailed assessment may not be necessary at that stage. But it should be possible to identify potential constraints that would inform more detailed site assessment in due course. 

Touching briefly on economics, the National Planning Policy states that planning policies and decisions should help to create the conditions in which businesses can invest, expand and adapt. And said in this context, the balance of reasonable cost against adequate certainty when considering archaeology is a really important question in this decision-making process and featured a good deal in the discussions we had that have informed this advice note, mindful that the income generated by a quarry is spread over its operating life. 

This brings into focus what is an appropriate amount of detail in evaluation when you're approaching a site? Before a planning application is made, an applicant clearly will need to assess the proposals, likely impacts and the costs of their avoidance or mitigation. Paragraph 189 of the NPPF was quoted a lot in early discussions and throughout, and this is one of the lines in that paragraph. So National Planning Policy, where we're trying to tease out what is meant by 'no more than is sufficient to understand the potential impact'. And we've endeavoured to do that in the advice note to unpack that, and that informs the content of today, whilst also, of course, recognising that decisions are made on a case-by-case basis. 

This links, also, with ongoing research that Historic England are funding. And in particular, at this stage, I'd like to flag a project that CIfA is leading on, which focuses on evaluation strategies. The project will be running a series of workshops in March and April this year, and one of those workshops will focus explicitly on minerals. And they're also on the lookout for case studies that they could examine more closely and tease out lessons learned. 

So if you would like to know more about this research project, as I say, led by CIfA, HE funded, in partnership with FAME, also. Or if you think you may have a case study, please do register your interest, and we've got a little mechanism to allow that to happen right now. So I'm just going to invite Rachel to put up a quick second poll, and if you can just answer 'Yes' or 'No', and then we can capture the email addresses for those that say 'Yes'. I won't be offended if you say 'No', but then I'll follow up separately with a bit more information and a mechanism through which you could suggest any case studies. That'd be great. Just give it another few seconds for people to register their interests. OK. That might be enough. 

Great. OK. Well, I will follow up with those who expressed an interest, and now that's the end of my initial scene setting, where I've touched on some of the issues we've tackled in the advice note. And here's where I turn to my colleague, Jane, who will explore identifying archaeological interest in more detail. Thank you. 

Jane [11:22] OK. Hello, everyone. I'm Jane Corcoran, science advisor for the South East for Historic England. And following on from one of the slides, that Guy showed us, 

what makes minerals extraction different to other development types? Well, quarries typically cover vast areas and in greenfield locations. They're very deep and likely to remove everything within their footprint, the full sequence of deposits right down to bedrock. Sand and gravel quarries, in particular, are often on floodplains or river terraces, and these are locations that have been exploited by people since early prehistory. 

Quarries are also of long duration. An operation activity such as dewatering will influence water flow patterns. These characteristics make minerals extraction sites important for archaeology. Because they're rarely located on brownfield sites, quarries have potential for relatively undisturbed archaeological survival. Their extensive nature gives good potential for recovering wide-scale evidence, which gives a basis for landscape archaeology. 

Sand and gravel quarries and voids and fissures in limestone quarries also preserve evidence for our very distant Palaeolithic past, which isn't accessible easily on less intrusive development sites. And the waterlogged nature of floodplains means that a range of minerals and evidence like wooden and other organic structures and artifacts, as well as palaeoenvironmental remains, could also be preserved. 

Woops. On to this next slide here. Well, archaeological interest is different for each of the different strata of a quarry. Above ground, quarries are likely to contain visible features such as-- Oh, I've got to click on this for-- Above ground, quarries are likely to contain visible features such as earthworks. In the topsoil, there's likely to be artifacts, such as lithic scatters, ceramics and metalwork. On previously cultivated land, this might be all that remains of former archaeological sites. Cut features and in-situ remains will exist within the topsoil. 

Well, there are various techniques that are suitable for mapping the surface, the topsoil and subsoil archaeology, like aerial photos and LiDAR, field walking, topsoil sampling, shallow geophysics, single-step evaluation trenching and strip, map and sample. But only the top metre or two is evaluated by these techniques, shown by this little white line here. They won't reach the deeper part of the quarry sequence, so that's all of this – I hope that that worked – which is also of archaeological interest and will also be removed by minerals extraction. 

These deeper deposits are often referred to as the natural. They include alluvium, [gluvium?] and windblown sands, which have built up at the same time as evidence of human activity. So these deposits are likely to contain archaeological features and prehistoric remains, like these late upper-Palaeolithic long [bleeds?]. Below this layer of natural, or below this upper layer of natural, the mineral body itself may preserve evidence of early humans and their environment, such as this mammoth tusk and the Neanderthal remains from Lynford Quarry. 

Sorry, click on this. So, I'll just have a sip of water here. So focusing on this deeper archaeological interest and the techniques we might use to access it, which of these techniques might help us understand the archaeological potential of the mineral body on a sand and gravel extraction site? Strip, map and sample, a deposit model, combined magnetometer and GPR survey or LiDAR survey. So, which is it? So, I think-- Are we going to have a poll here? 

Alice [16:32] Sorry, Jane, I am just dragging it across now for you. 

Jane [16:33] Oh, that's OK. I thought I'd done something wrong. It was all so silent. I thought it was me. 

Alice [16:38] No, it was me having a dexterity issue with the mouse. 

Jane [16:43] 100% deposit model. Absolutely. Yes. A deposit model-- Oh, it wasn't 100%. Sorry, people are still doing it. Well, a few people thought split, map and sample, and so often on a quarry site, strip, map and sample is the main means of archaeological investigation, but that totally forgets about the deeper part of the deposit sequence. And LiDAR survey, also incredibly useful, but it doesn't reach deep features. So it might, as in that last slide, identify palaeochannels, but these are relatively recent palaeochannels in most cases. So, the answer was a deposit model, which helps us to look at the characteristics of the whole sequence of [indistinct], and this will help us understand the potential of each of the strata present including the sand and gravel minerals body. 

So have I moved? Yes. So deposit models are part of a geoarchaeological approach. They focus on topography, geology and deposit characteristics. They are most useful when deposits of archaeological interest are deep and of natural origin. So a geoarchaeological approach is well suited to quarry investigation. Deposit models are usually informed by boreholes. These might be historic data downloaded from the BGS website, purposive geoarchaeological boreholes or collected by a geoarchaeologist as part of a geotechnical investigation of the quarry. 

The cause of borehole logs feed into schematic sections drawn across the site, illustrating the depth and distribution of deposits and helping to divide the site into areas of different deposit character and archaeological potential. And this will help in designing evaluation strategies such as the spread and depth of evaluation trenches, whether and where sondage is and test pits are needed, or whether you need additional boreholes, and they'll also help to identify where shallow or deep geophysics is likely to be needed and might work best. 

Magnetometer and other standard geophysical surveys are useful for shallow sequences that just extend into the subsoil, but when we're looking at the full quaternary deposit sequence right down to bedrock, often many metres of sand and gravel, we need to use different types of geophysics. And these will include electrical resistivity transects and electromagnetic survey. These provide a means of imaging deep sequences. They can help to identify depth and distributions of deposits of different character, as well as the potential for buried landscape features like palaeochannels or ancient cliff lines. 

These surveys cover far more extensive areas than that seen just in a 10cm diameter core from widely spaced boreholes. However, we need the information such as deposit sequences from boreholes – and I think you can see some here – to help us interpret the geophysical results, so a combination of boreholes and deep-penetrating geophysics, feeding into deposit models, is an effective first-step approach to evaluating the deposit sequence of deep and extensive quarry sites. 

We've already mentioned that quarries are an important source of Palaeolithic evidence. 

Unlike later archaeology, Palaeolithic evidence isn't about features or structures, but it's about deposits and the objects they contain: stone tools, animal bone and evidence about the contemporary environment. Therefore, an understanding of these products should be the focus of all stages of investigation from the desk-based assessment onwards and will involve similar evaluation techniques to those we've just discussed: boreholes, test pits, sondages, deep geophysics and deposit models. 

These techniques will identify areas that might have greater potential for Palaeolithic evidence and enable a strategy for more detailed recording to be developed. Typically, this might involve an intermittent watching brief, together with training sessions for quarry staff to recognise Palaeolithic evidence, as well as section-phased recording. Because of the huge size of quarry faces, this is increasingly being done by means of laser scanning. 

And some indication of the size can be seen on this. There are two-- Have I just hidden it? There are two people there – tiny little fingers in this huge quarry face step section. So they're really massive areas that we're talking about here that need recording. Section recording will also involve sampling for dating, such as here – optically stimulated luminescence dating. It's beyond the range of radiocarbon, the Palaeolithic and palaeoenvironmental assessment. 

Where quarry sites are located on floodplains, waterlogged remains are likely to be preserved by high-water tables, so there's good potential for recovering rare evidence and new information that doesn't survive on drier sites. But excavating and conserving waterlogged material can be very expensive, and its rarity and significance might in some cases lead to a decision being taken to retain remains as an island within the query. Sorry, I don’t know why that clicker's on there. There. 

However, it's important to assess whether the remains are in a good enough state of preservation to survive reburial, and also to consider how operation activities such as dewatering might influence water flow patterns, as this could impact on the burial environment of any remains retained within the quarry and nearby, which might lead to deterioration of their state of preservation, which reduces their archaeological significance. If there's any doubt about their survival, then detailed recording and excavation might be the best option for understanding the archaeology. And this was the case it Must Farm in Cambridgeshire, illustrated here, where the decision was taken to excavate rather than retain the wooden remains of late Bronze Age roundhouses at the edge of an Oxford Clay extraction pit. 

The wide scale and long duration of a quarry enables the evidence to be seen from a landscape archaeology perspective, looking beyond individual features and groups of features to examine relationships between past communities and their surroundings. 

GIS mapping allows digitised information from every stage of investigation to be combined. And a deposit model should be a component of this landscape mapping. 

However, big data sets and the phased investigation of quarry sites, often over many years, can lead to all sorts of issues relating to data management and accessibility during the lifetime of the fieldwork and into the post-ex and publication programme. As well as this, staff and contractors will change, new techniques will emerge and research questions will evolve. Tackling these issues is all part of the staged approach to assessing the archaeological potential of a mineral site. And this is a good point to hand over to Sandy, who will tell us more about this. 

Sandy [24:52] Thank you, Jane, and good afternoon, everyone. Just by way of introduction for those who don't know me, I'm the team leader of the Greater London Archaeological Advisory Service, but I'm going to be talking as much about experiences in previous employment as a planning archaeologist in Buckinghamshire and Northamptonshire, so many of the examples you're going to see come from there. 

I'm going to give a rapid overview of how the [indistinct] says we should assess archaeological interest, what implications that has for the different roles involved in that process whether you're a planning archaeologist, an archaeological consultant, a quarry company or a minerals planner. And to do that, I want to sort of focus initially-- well, perhaps just looking at this slide first. One needs to know. Wherever you sit in in those different roles, you need to know in advance whether you have a major archaeological issue on your site, such as a Roman villa, on the left here, or as Jane's already referred to, complex waterlogged archaeology, that can appear on many of these sites. Or are the issues less, or lesser, or different. So you need to understand before the planning decision is taken, and that's what this slide leads us to, which are setting out the steps which should be gone through from site identification, whether that's in a local plan, or through some other process, through to an actual decision. 

And the first thing to emphasise is that archaeology has been engaged with the minerals planning process, as I'm sure you all know, for many, many years, decades, stretching back even before the publication of PPG 16 in 1990. So in most areas, where mineral extraction is going to take place in the future, there is a long legacy of investigation. Very few mineral sites are in areas which have not seen any investigation. 

So first of all is to find out what's already known, not just from the site but from the area, so that you understand the context. Then to hold a discussion to decide what the key issues are to identify what additional information is needed to make a proper assessment of significance, where the various assets that have been identified sit within the scale of significance, from national importance down to more regional or local significance, and then to see what you can do to reduce harm to that significance, bearing in mind the nature of mineral extraction makes that perhaps more difficult than for some other types of developments, and what positive contributions mineral extraction can make, because they are significant and perhaps not always given, the way perhaps they could be accorded. 

How does that link then into policy? So you make sure you've made the applied policy correctly in reaching a planning decision, whether that's favourable or unfavourable. And if favourable, what planning conditions ought to be applied and that they are properly justified and meet the necessary tests? 

So just looking at significance and potential, the best way to start, I think, is first of all, for the commercial quarry company to get a good archaeological consultant on board, who's familiar with this topic and the area that they're working in and to get that person to come and talk to the planning archaeologist and to go through the various bits of information that you can see listed here and then anything else that's relevant to think about what might be on the site. There may already be good information for the site. There may be less, but there may be information from surrounding areas that can be drawn on to help identify what the key issues are. The point is to agree on that scope early on. 

In some parts of the country, there are existing studies, which can be drawn on to do this. So here's an example from Warwickshire, and there are many other studies like this, which were funded under the Aggregates Levy Sustainability Fund or indeed have been done for other purposes at other times. Very, very useful, but remember they are point-in-time statement. This one dates from 2008, so you would again, as a commercial archaeologist, need to talk to the planning archaeologist to say, 'Well, how have things moved on since then? Are there new discoveries, different perspectives? How much weight should we put on this? 

The other obvious thing to consider is the impact. We know quarries are large holes in the ground, so the loss of buried archaeology and Palaeolithic archaeology, as Jane's already alluded to, are likely to be key issues. But which of these are relevant to the particular case? So is the Palaeolithic relevant or not? That depends on what the geological body involved is. Is there a high potential for environmental archaeology? Are we looking at waterlogged palaeochannels? Is that a question? Are they visible landscape features, such as earthworks or hedgerows, that need to be taken into account? Are there nearby historic buildings or scheduled monuments where setting effects are going to be considered-- need to be considered? 

Dewatering. Is that an issue? Are there nearby sites which may be vulnerable from changes in the water table? And what benefits might you-- Start thinking about those early on rather than as an afterthought. What positives could come out of this for the historic environment and for local communities' engagement with the historic environment. So those are the things to consider and identify which are the most important to your site. 

So applying the NPPF to all of this. Here are just some key points that I think just need to be emphasised, that all planning applications that affect, or are likely to affect, heritage assets must consult the historic environment record. That's been there in the NPPF since the start. There was a legal case, not related to minerals, the year before last in which a planning consent was struck down because that hadn't happened. And given the fact that minerals applications are very likely to affect the historic environment, and particularly archaeology, that is a risk you just don't want to take. So make sure you've done that. 

That then leads on to, as we'll come to talk about, this stage process of desk-based assessment and field evaluation in many cases in order to properly identify and assess the particular significance of heritage assets. It's not good enough to just say, 'Well, there might be some archaeology here and broadly what that might be'. That's not normally sufficient. You do need to actually identify and assess, which will mean going a bit beyond that. 

And then avoid or minimise conflicts. So it's not simply a case of saying, 'Well, we think there's going to be some archaeology on this site, so we're just going to strip back a sample and record it. Again, that's not avoiding or minimising conflict. So there will be some cases, perhaps, where you can say on the base of existing information that the archaeological potential is sufficiently limited to allow that process, but in most cases, you will need to go beyond that. 

OK, so the HEAA emphasises high-quality, detailed, desk-based assessments. Now, as all the archaeologists in this virtual room will know, there's a lot of debate about-- there has been a lot of debate about the quality of desk-based assessments, and they vary tremendously between some which basically just regurgitate what's on historic environment record and add a few historic maps to it, to those which are really thoughtful and useful in leading forward our strategies and decision making. So I would emphasise to anyone in the room, and particularly anybody who might be commissioning this sort of work, is that the cheapest quote for a desk-based assessment is unlikely to be the best, and it is quite likely not to be the most cost-effective either. 

So you need somebody, as I said already, qualified consultant, freshly qualified consultant, who knows the topic and ideally knows the local area and who can work constructively with the local authority archaeologists to go through and consider all these different issues around what the potential of the site is, what the state of preservation might be, consider broader issues, such as whether setting studies are required, and engage in a constructive discussion around the issues of field evaluation, including the knotty topics of trial trenching and how far to go with that, which brings us on to that question. 

So when might field evaluation be necessary to inform a planning decision? And this is not exclusively to minerals. This would apply in other cases as well, but it's an assessment of what is the nature of the archaeological interest. Is it such that it might be necessary to modify the proposals? Do we understand the significance of what's on a site? Particularly, but not exclusively, could that archaeology be of national importance, and therefore subject to the policy regime that applies to listed buildings or scheduled monuments and therefore takes us into a different planning situation? What is the degree of harm? Obviously, in many cases, we would be looking at substantial or complete loss from extraction, but in other cases, the harm might be minor, for example. If we're looking more, say, at a building at some distance from the quarry, it might be that the setting impact will be relatively modest. 

And therefore, you're thinking, could the proposals-- is it reasonably plausible that the proposals might be modified as a consequence of the results of an evaluation? And/or could the conditions be influenced by that? You would need sufficient evidence, obviously, to justify conditions in the first place, but the way they're worded on what they cover might be different depending on your understanding of significance and impact. And don't leave these critical decisions to be hidden away in planning conditions saying that the investigation just has to take place, but we don't really know what we're investigating and what the implications of that are going to be. 

The HEAA emphasises, and here's one of the boxes that Guy mentioned earlier, it emphasises a staged, iterative approach to evaluation, starting with desk-based assessment and moving on through geoarchaeological assessment, non-intrusive survey, geophysics and aerial photography and such like, and then onto intrusive trial trenching. Not all of them will be applicable to all sites, and it depends on the questions. If you think-- If you're looking for Mesolithic flint scatters, that's probably a different suite of evaluation techniques than if you think you might have a Roman villa, for example. So again, that's part of the dialogue, why the dialogue is so important and why just using standard trial trench percentages is not something that we are proposing in this HEAA. 

To take an example, here's a site in Havering on the edge of London towards Essex, and you can see here an aerial photographic survey was done, and it picked up-- Sorry, I can't use the pointer, so maybe that will work. Yes, you can see it picked up a small enclosure here and a few other features, a lot of natural features, on this quarry site. That was then followed up by geophysical survey, which picked up a corner of that enclosure and a few other features, again suggesting that there was some archaeology here but not a vast amount. But as I said, think about context. Many sites have been investigated in this area. We strongly suspected this was an unsignificant underestimate as to what's there. Trial trenching initially did a first stage, which confirmed these features were actually archaeology. They weren't some sort of natural phenomenon. And also, those trenches found additional features, which not surprisingly haven't shown up in geophysics or aerial photography, which don't pick up small features like pits and post holes very well. So that we then move to a second phase of evaluation with more extensive trenching. 

And then, as part of the mitigation to further strip, map and sampling, and you can see the results of that showing up over here on the top right. And in the bottom right, a major find that came up a couple of years ago of a Bronze Age hoard. So you can see the iterative approach is giving a much greater understanding, and we should be aware of the limitations of non-intrusive surveys and desk-based assessments. We need to be conscious of that. 

Moving on to assessing significance, these are the factors that are laid out in GPA2. We'll look at the nature, the extent of significance and its level, whether it's of national or less than national significance. Particular reference to research frameworks in relation to understanding how the potential of archaeology to advance understanding if investigation takes place, and as I've already alluded to, I think the public value is something which probably should be given more emphasis than it generally is, or sometimes is. National importance is a key issue aside from planning decisions. Footnote 63 of paragraph 194 covers this, flags this up. And of course, you can identify national importance in a number of ways. At the top level, there's things which are already scheduled, but it's unlikely they would be allocated for mineral extraction or appropriate to grant consent. 

But then there are a number of other situations, sites which are formally designated-- sorry, formally assessed but not designated, sites which are outside the scope of the Ancient Monuments Act such as prehistoric flint scatters. And there are a number of sources of information you can go to to assess whether a site which isn't designated is actually of national significance – the DCMS-published principles of selection for scheduled monuments, which give you some basic principles, and there are scheduling selection guides from Historic England to consider. And also sort of consultation with your local inspector of ancient monuments may, and historic England, may help with that as well. And we should also be passing note that sometimes archaeological interest can be associated with other designated assets, such as listed buildings, and may contribute to the significance in that way. 

So where's all this going to lead? Well, to take a more complicated site, where you may well end up with a zoned mitigation strategy without some areas being preserved, others subject to detailed investigation and others perhaps being dealt with through watching brief or even scoped out entirely. And here's an example from the Colne Valley of that type of strategy. But the best-laid plans of mice and men, inevitably there, archaeology does throw up unexpected discoveries that despite the best efforts at evaluation-- There are some things which cannot be realistically and reliably evaluated for isolated burials. One example, hoards, are another very small but very important discoveries. This one is a princely burial that was discovered at Wollaston in a [indistinct] valley back in the 90s, which was a really, really major find that I had some peripheral involvement in. 

But all you can do is minimise the risk. Perhaps look at nearby sites. Have things come up in this area before? What's the level of risk? Allow reasonable contingencies. There is the possibility of Historic England Grant Aid as a last resort. HEAN does cover the criteria for that, but you must have done the proper evaluation in order to be eligible for that. And celebrate your finds. I mean, this find is on display in the Royal Armouries in Leeds and has been on display locally, so it's been a really-- it was a really big thing. And it's called The Pioneer Burial because that was the company who paid for its excavation and conservation, which brings us to post-excavation. Simply allow for it in the programme. I think that's all I'll say for now. Don't forget restoration after use. This is where public benefits can come in, an opportunity to put something back into the local community that's been affected by mineral extraction. Think about museum exhibits, for example, as in the case of The Pioneer Burial – heritage trails interpretation, that sort of thing. 

And so to recap, this is the process. You need to go through it to identify what the issues are. Go through these logical steps. Make an informed planning decision with properly defined mitigation, and identifying those significant public benefit opportunities as well. Thank you. And we're moving over to Sasha now, who's going to talk about two sites in Somerset – case studies. 

Sasha [45:05] Hi, good afternoon, everyone. My name's Sasha Chapman. I'm the inspector of ancient monuments working in the South West region, and I'm going to be talking about mineral extraction in two case studies. Firstly, I wish to thank Cambridge Archaeological Unit, who kindly provided me with most of the images for this presentation, Nick Dunn of Land and Mineral Management, Wessex Archaeology and both Ham and Doulting Stone Company and Castle Hill Quarry Company, who have allowed me to discuss the sites today. 

I'm going to be discussing two case studies in Somerset that are both active quarries and both have considerable but different archaeological constraints. Hamdon Hill, known locally as Ham Hill, is a scheduled monument and one of the largest hillforts in England. The hillfort encapsulates a multi-period archaeological landscape dating from early prehistoric through to the post-mediaeval period. This image is an aerial view of the quarry, showing the 2011/2013 excavations. 

This is a highly unusual situation, where active quarrying is being carried out on a nationally important and protected hillfort. It is purely the value of the stone, in heritage terms, that has allowed this to happen, so that the need to protect the hillfort is being balanced against allowing access to this resource. Stone has been quarried here since Roman times, and it is the only viable source of Ham Hill stone needed to repair many of the mediaeval ecclesiastical buildings in the area, as well as many prominent listed country houses in Somerset and Dorset. In his seminal book, The Pattern of English Building, Alec Clifton-Taylor described it as one of England's most seductive stones. 

This is Ham Hill in 2011 showing the quarry in the foreground and archaeological excavations behind. The new advice note seeks to ensure that informed decisions are made regarding the level of archaeological assessment and understanding needed at each stage of the planning process. Both the local authority, archaeological advisors and Historic England will be able to advise on the impact of known assets and their setting and on the potential for heritage assets as yet unknown to be present. Here at Ham, the constraints and archaeological considerations are considerable due to its status as a scheduled monument. If works are proposed on, or affect the setting of, a scheduled monument, early discussions with Historic England are recommended. 

Both planning permission and scheduled monument consent is required at Ham, and this includes consent necessary for the initial trial trench evaluation phase. The Secretary of State for Digital Culture, Media and Sport provides a framework for considering, whether proposed works will or have potential to cause harm to the significance of a nationally important scheduled monument. And the Secretary of State gives great weight to their conservation but also will weigh the harm against the public benefits of the proposal. There is a balance that needs to be weighed, and whilst it's recognised that there is potential for harm to and loss of significance from extending quarrying operations, a programme of archaeological work will be necessary for the significance, harmed or lost, to be captured and recorded in order to add to our knowledge and understanding of this important asset. 

Pre-application engagement is necessary in order to understand and assess the potential impact. An environmental impact assessment is usually required, and this will allow for cultural heritage to be considered through the screening opinion and scoping opinion stages. Desk-based assessment is essential to inform a question-orientated evaluation and strategy. A good desk-based study reduces the risk of the unexpected. The Somerset Minerals Plan says that a desk-based assessment will be required as a minimum for proposals that impact on the integrity and/or setting of a heritage asset, such as a designated area of high archaeological potential, or areas with potential archaeological interest. Non-intrusive assessments such as LiDAR and geophysics, that James referred to earlier, are useful tools and can be used in the initial stages to determine where specific features could be avoided or be specifically targeted through trial trench evaluation to understand the nature of the archaeological deposit. 

At Ham, trial trench evaluation has been and will be used to determine the presence or absence of archaeological features. The area proposed for extension is an area where there has been historic quarrying and spoil tipping, which means it's been difficult to determine the depth of archaeological deposits. With most quarrying operations, the extensive scale and depth of archaeological interest and almost complete deposit removal will require a geoarchaeological assessment to be included in the desk-based assessment, where the overburden or where there is potential for archaeology to be in the mineral body itself. 

The excavations in 2011/2013 at Ham encountered surprisingly intact ramparts beneath quarry waste. This image shows the stone-constructed rampart in one of the trenches. This shows how important a stage approach is in order to accommodate surprise finds and appropriately deal with them. Where there is uncertainty, it is important that excavation programme and sampling strategy are sufficiently adaptable. 

A distinct assemblage of charred plant remains and animal bones has been recovered from excavations at Ham since the 1980s. This image is of brassica nigra seeds otherwise known as black mustard. At Ham, they've been found in pits in significant numbers, suggesting they may have been a crop. Emmer wheat has also been found, and this is unusual as spelt wheat predominates in the Iron Age period. Both broad beans and a single pea have also been identified at Ham, and the presence pulses is significant as they are rarely encountered on Iron Age sites. Future sampling will aim to recover animal bones such as dog and rare crops such as pulses and black mustard, which could further our understanding of agricultural practices, crops and processing, as well as environmental conditions during the Iron Age period. 

Community engagement and educational opportunities provide additional benefits. At Ham, it was possible to have students learning alongside volunteers, and this image shows Cardiff University students and local volunteers working together, which provides opportunities for allowing volunteers to work alongside trainee students under the guidance of professional archaeologists. The earlier archaeological evaluation provided opportunities for this type of engagement. 

Early excavations at Ham have encountered Palaeolithic and Mesolithic flint, as well as a large number of stone implements including axes and arrow heads and material indicative of Neolithic settlement. Where prehistoric lithic scatters have previously been identified or have potential to be present as identified for a desk-based study, we would recommend a specialist to be involved to advise in the initial stages of the project, and this advice is included in the written scheme of investigation. Here, Cardiff University students are excavating skeletons, and this image shows rain protection measures. Up-to-date advice on appropriate techniques and specialist advice can be sought from the Historic England regional science advisors. 

Human skeletal remains provide a rich resource of evidence about our past. It is important if human remains are anticipated that the project has a specialist osteoarchaeologist who is able to advise at the outset. During the excavations at Ham, human remains from the late Iron Age period were uncovered, and analysis revealed fine cutting marks on many of the bones, which were thought to relate to ritualistic practice. Other the skeletal remains had blunt trauma, highlighting the connection between conflict and ritual behaviour within the region at the time. 

Right, myself and my colleagues were discussing this earlier, so I'm not exactly sure how you pronounce this place, but I'm going to go for /kənuːt/ but other people have suggested it's /sinwɪt/, and for other people, or for fans of Bernard Cornwell novels, apparently it featured in a recent programme of his. But I'd like some feedback if possible, but I'm going to go for /kənuːt/. 

So this is my next case study. Castle Hill at Cannington is an active quarry, primarily extracting Carboniferous limestone for use in the aggregate animal feed industry. The quarrying operations are adjacent to two scheduled sites. I've highlighted the scheduled area in blue. It's an Iron Age hillfort, which is on Historic England's Heritage Risk Register, and a Romano-British settlement immediately south of the hillfort. They're both adjacent to each other, so they form one sort of scheduling, even though they're separated. 

The site clearly has the potential to include heritage assets with archaeological interest. So with any expansion and appropriate desk-based assessment and field evaluation will be necessary to understand the physical impact on potential archaeological remains. It is important to understand the impact the quarrying will have on the significance of the two sites from development within their setting. The hillfort is approximately five hectares and survives as an irregular-shaped enclosure, defined by slight rampart with a lightly buried outer ditch. 

It is possible to appreciate that the hillfort provided strategic views to and from the site, and despite its overgrown state, it is a prominent feature in an otherwise relatively flat landscape. The lower-level earthworks represent the settlement site that lie on the lower ground as you approach the hillfort. The settlement survives as low-lying earthworks. Again, their overgrown nature and lack of interpretation means that there are opportunities here to promote a wider knowledge and understanding of the site. The continuation of quarrying on site will clearly result in a change of setting, resulting in harm to the significance of the hillfort and later settlement site. 

It is also important to recognise the impact that noise and dust and traffic will have on the setting of these nationally important archaeological sites. It will be possible to mitigate some of the harm by improved management of the hillfort, and the management plan would clearly offer opportunities and benefits to both the appreciation of the landscape and wider ecological benefits. It may be possible to include the management of the site within one of the new environmental land management schemes known as ELMS. 

The archaeological implications here, as with many mineral sites, are considerable. As outlined previously, a desk-based assessment is an important element of any scheme. Here at Cynwit castle, previous excavations have revealed a large amount of burials and a possible temple site. There is also anecdotal evidence that the castle was the site of a battle, and it would be prudent to explore this further. The discovery of mass graves, for example, could significantly increase costs and may lead to the quarry expansion being unviable. 

Any extension of quarrying will require archaeological evaluation in the immediate area and beyond in the wider field in order to establish if there is any significant archaeology between the settled settlement and the wider field area. A LiDAR survey across both sites would be useful and to enable a wider understanding of the extent of the settlement and the relationship between the settlement and the hillfort. The result of this could lead to the interpretation of the site on the public right of way along the field edge, all of which contributes to improvement and understanding of the settlement sites and the hillfort. This could include interpretation of the wider site that included the now-lost cemetery site and the possible temple that was removed during the 1960s. 

An important element of the project will be the restoration plan, and whilst the visual impact long term could be considered as temporary as the site will be backfilled, often the ground remains open for a considerable period, resulting in long-term setting issues. At Cynwit, the restoration phase will need careful management. With enhancements gained from improved management of the hillfort, there is potential for the development to provide opportunities to conserve and enhance the heritage assets here. 

This is an image of Glastonbury ware Iron Age poetry. It was found at Ham. It is important that post-excavation finds analysis is included into the written scheme of investigation. The WSI is central to all archaeological projects. It sets out the current understanding of the site and area, development proposals and their impacts and the approach to undertaking the archaeological project. The research questions will be identified and linked to the regional research framework, which clarifies how the field worker will contribute to-- how the fieldwork will contribute to wider understanding of the past. The WSI is likely to be central to any planning permission granted and will be written into the archaeological planning conditions, which must be complied with and satisfied before they're discharged. 

Archaeological responsibilities and costs do not end when the fieldwork is complete. And it is through the process of analysis, dissemination and archiving that provides the greatest added value on wider public benefits. I was asked to show the reality of post-excavation work because apparently, my first slide was too sleek. So this isn't even that bad for post-ex work, but whilst the previous image just shows the positive end results that come from a well-thought-through project, the reality is a huge amount of post-excavation work that often takes more time and is more costly than the actual excavation work. 

At Ham, tools were hugely popular, with over 4,200 visitors, and one of the aim of the advice notes is to ensure that archaeological understanding is advanced, and that opportunities are taken to share those findings with the public so that whilst there can be considerable harm from allowing mineral extraction on and close to scheduled sites, if appropriately managed, the damage can be offset. Where work is carried out to deliver public benefits, as being the case at Ham, and with the work planned at Cannington, the relatively small costs involved far outweigh the public benefits gained. That's the end of my talk. Thank you very much. 

Duncan [01:00:38] Great, thanks ever so much, Sasha. I realised we were running slightly over time. So I had devised some fiendish questions for the panel, but I'll just run through one or two quick points, I think, that came out, and maybe we can pick some of this up and kind of take it away and think about it. There was a point about public benefit, a question around how can you measure it and give appropriate weights to it. There is GPA 2 good practice advice note, number 2 about managing significance in decision taking in the historic environment, which has some advice on that. But I think it's a fair point that that's probably something that we need to explore further. 

There was a point about national importance. Historic England's working on clarifying that in relation to scheduling and what the NPPF says, so we may well be exploring that further in some written guidance in due course. There was a point made earlier on in the chat around post-excavation publication. Richard Brunning was emphasising, I think quite rightly, about the shift, inevitable shift perhaps, towards digital publishing. It offers quite a few benefits. Although it may not help the bookcase behind you when you do your Zoom calls, actually, in many ways, it's more flexible and it's cheaper. 

[Kasia?] picked up about website content, as well, and I think there was another point around-- I think [you sense?] those were the main points. So I'm just very quickly going to ask the panel whether they have anything in terms of what they've heard from the other speakers or anything they've seen in the chat that they just want to pick up on. So, Sandy, you're unmuted. Does that mean you want to say something? 

Sandy [01:02:29] Well, I was wondering if you were going to ask, but yeah, I saw the question about public benefit, and I think it's very much a live issue, as you said, Duncan. It's one that I think there are a few pointers in the NPPF and GPA 2, but I suppose because that concept has to cover the whole of the historic environment and tends to be, I think, the emphasis tends to be weighted on the built environment. There's perhaps a little bit more need for us to think about what that means in archaeological terms and how we might need to phrase things slightly differently. The sort of picture we're looking at, at the moment, of tourists being taken around an archaeological site is not, I think, explicitly covered, at least in the NPPF, and I think it may get a mention in GPA 2, but it's very difficult to know how much weight for a planning authority or to give such things. Great to hear that there are 4,000 people visiting a hillfort in Somerset, and that should be given rather more weight than if four people are shown around a site somewhere else. So yeah, how do we weight these things, I think, is the great challenge we need to explore further. 

Duncan [01:03:48] Thank you. Yes, good point. Does any of the other panel want to come in on that particular point? I think one of the things that I was struck with-- 

Sasha [01:03:56] Sorry. 

Duncan [01:03:57] Yes, please come in. Sasha. 

Sasha [01:04:00] Sorry, it's Sasha. 

Sasha [01:04:01] I was just going to say it's not just about doing-- I can see my image in front of me. It's not about just having-- sort of doing public tours. You could do a recording, or the artifacts could be in a museum. It's just about engaging people in sort of ways possible and sort of introducing that early on in the project. 

Duncan [01:04:28] Fine. Thank you, yes. I see in the chat, Rebecca Hatton has just asked about definition of public benefit, and somebody helpfully has answered that, but I think the NPPF, in a sense, is that and the guidance that sits beneath that from government and the PPG. And also, there is some information on Historic England guidance, so you could google that and track some of that down. But I think it's very much an art rather than a science. I suspect it's always going to be that way, but I do take the point that trying to be a little bit clearer on that in relation to archaeology and mineral extraction is important. And I think one of the issues in the past few years, when we've been discussing potential joint guidance, was about the proportionality of necessary information and proportionality of this kind of additional wider work, but obviously, public benefits often bring benefits to the company that's doing the extraction, as well as to furthering archaeological knowledge. 

So I think probably given the time, although I'd love to go on and ask some more questions, I probably need to draw this to a close. So first of all, I'd just like to thank all the speakers, to Guy, Jane, Sandy and Sasha, for really interesting presentations and interesting images and visuals, so thank you very much for that. Thank you very much for the audience and taking part, showing your interest, taking part in the chat and hanging around because almost all of you are still there. Thanks to Rachel and colleagues for setting this all up. And I think now I'm going to hand back to Rachel for final farewell. Thank you.