In amongst all the turmoil of the cuts being announced (and I don’t wish to demean anyone whose career is on the line over this) but a small change that has gone largely unnoticed is going to have a devastating effect on geoconservation and bioconservation work in the UK.
A large proportion of this kind of work has been funded from the Aggregates Levy Fund. This is a tax placed on quarries extracting aggregates and was designed so the funds raised could be put back into the communities that are affected by the noise, dust and traffic generated by these quarries. This has allowed geological and wildlife groups to conserve local sites and produce management plans to enhance and promote them. The group that I am now leading, Geoconservation Staffordshire (formerly Staffordshire RIGS) has used the money to produce three geotrails that promote geotourism in the affected areas and bring in visitors to help support the local economies. The UK government has quietly changed the rules in that the Levy remains but they are going to keep all the money!
This means that much geoconservation and bioconservation work will stop or be severely curtailed. We have so much work to do. This is a SSSI (site of special scientific interest) in Staffordshire. It is hugely important to Quaternary Geology. It is a type section for the Devensian in the UK. It is completely overgrown.
It is now going to be very difficult to conserve sites like this and much of our geological heritage could get lost. The appropriation of the Aggregates Levy Fund for a purpose for which it was not originally intended is also going to hit bioconservation hard as well.
The section here is interpreted as Late Devensian Irish Sea glacial till overlying Middle Devensian fluvioglacial sands. Fortunately for this site, money has been obtained from other sources to conserve this section (and we had permission to expose a small section of it here), but as I mentioned, this is a classic site. Other sites will not be as fortunate.
Keele University, where I work, has a plan to become self-sufficient in energy. This involves installing a variety of energy sources such as wind turbines, solar panels and ground source heat pumps, but one of the major projects that is currently underway in pilot form is the extraction of methane from the coal seams beneath campus. I was fortunate enough to be allowed to visit the drill site at the end of last week.
The first impression of the site is its relatively small size, about the size of a football pitch and how quiet it is. From 100 metres away the road noise from the M6 motorway is louder.
The drill rig is also smaller than I expected it to be and, as can be seen in the image, is actually mounted on the back of a truck. The drilling plan is shown schematically below [not to scale].
The ‘mother’ borehole (in blue in the diagram) is drilled to about 1000m depth using directional drilling in an ‘S’ shape, shallowing through the target coal seam, and then steeping downwards to form a sump. This is the current stage of the drilling.
The drill bit will next be withdrawn back up the hole to the level of the target seam (in this case the Great Row Coal) and a spur drilled along the the coal seam itself, slightly dipping upwards (in red on the diagram). Water then drains from the coal seam to the sump where it is pumped out. The draining of the water decreases pressure in the seam and stimulates the release of methane from the coal.
If this proves successful, and the mother bore is already showing promising signs of methane, then the next stage will be to drill a number of other bores through a variety of seams, extract the methane which will then be piped to the University’s boiler house.
Keele is blessed with several unmined coal seams below campus. The land on which the university was built was once owned by the Sneyd family who built their family seat, Keele Hall, here. Whilst making, and losing, a fortune from coal mining in North Staffordshire they had the common sense not to undermine their own house!
The other thing that we are interested in are the bottom hole temperatures. North Staffordshire coal mines were amongst the warmest in the country, and if, as we expect, the downhole temperatures are around 50-60°C then we also have the potential for geothermal energy as well.
Disclaimer: As always, this blogpost represents the views of myself only, and are not necessarily those of my employer.
Now that teaching and exams have finished for another year, thoughts turn to the field. Whilst the likes of Geotripper and Dr Jerque get to visit some spectaclur and unspoilt places, my field work takes me to somewhere interesting but not quite as pretty. These are Beech Caves in Staffordshire.
The caves aren’t natural but the result of mining the Triassic Bromsgrove Sandstone (formerly the Keuper Sandstone) for building stone. The pillar and stall workings were begun possibly in 1633 for the construction of the nearby Trentham Hall. The Trentham records for August 31st 1633 note a Roger Low being paid 22 pence per score for carrying 130 foot of stone from Beech.
This was the first of several halls at Trentham, being rebuilt in 1690 and again in the 1830s, ultimately becoming one of the finest buildings in England. Unfortunately, pollution from the growing Potteries conurbation filled the lakes with sewage and the magnificent hall was abandoned and demolished in 1912. The gardens did remain and now the lakes have been cleaned and the gardens refurbished (well worth a visit) there are plans to rebuild the hall as a five star hotel.
Beech Caves still show the evidence of the hand-pick marks by the miners as they followed a layer of pale-coloured sandstone dipping gently down into the hillside. The thick overburden made mining rather than quarrying a more attractive proposition.
In more recent times the caves were probably used as a munition store in the second world war but lately they have been used for raves and other undesirable activities. The caves are now litter strewn and graffiti covered. The land owner and the local council now want to block off the entrances to stop the ne’er-do-wells from getting in. However, in doing so, they will bury an important piece of Staffordshire’s geological history. It would be a great shame if these historic pillar and stall workings were lost. Whilst understanding the landowner’s concerns for the site, it is hoped that some limited, secure access can be maintained for historians and geologists alike.
Reference: Middleton T, 1986. A survey of Beech Cave, Staffordshire. Bulletin of the Peak District Mines Historical Society, 9, 401-403
Two more small local earthquakes have occurred in Stoke-On-Trent following on from the two that happened on Christmas Eve and Christmas Day. Both were magnitude 1.8 and are probably related to old mine workings beneath the city.
I was convinced that I felt an earthquake last night. I was just drifting off to sleep and must have drempt it as there was no record of our seismometer when I got into work this morning. However, in checking my iPhone for (non-existent) earthquake reports I did come across two local earthquakes that happened over Christmas whilst I was away in Morocco that I would have otherwise missed. This is quite a coincidence as I can’t remember any local earthquakes in nearly five years.
The first was on Christmas Eve, magnitude 2.1 and felt in Stoke-on-Trent, Staffordshire, UK, the second magnitude 1.7 on Christmas Day and not felt. Here are the seismograms recorded at Keele University on our School Seismology project seismometer.
When I first came to Keele University in the late 1980s, little did I realise the seismic activity of the area related to the area’s coal mining heritage. I have felt over a dozen local earthquakes over my time here.
Since the latter part of the nineteenth century several areas in North Staffordshire have experienced occasional series of Earth tremors which are known locally as ‘goths’ or ‘bumps’.
Between early 1975 and August 1997 the Hanford and Trent Vale areas in the southern suburbs of Stoke-on-Trent over 50 events were felt, the largest being a magnitude 2.8 event on 15th July 1975 which caused some local damage. The earthquakes were associated with the extraction of the Ten Feet seem which was mined between 1973 and 1977 from the Wolstanton pit. Activity centred on the region above the face and the pillars of adjacent seems. Events could not be correlated with any of the major or minor geological faults in the area.
Swarm activity started again in May 1980. Activity was located in two centres, one near Cobridge, the the Banbury seem was being worked, and one near Talke, where no mining was currently ongoing. 11 events were felt during this period including the magnitude 3.3 Talke Pits event on 9th November 1980, the largest local event felt in recent times.
Between 1982 and 1987 activity in the region was very low, although the Lleyn Peninsula earthquake on 19th July 1984 was felt strongly in Staffordshire. On 2nd July 1987 an earthquake was felt in the Hanley region. A series of events the occurred in the Smallthorne district over the next few years culminating in a magnitude 3.0 earthquake on 4th March 1990. A month later, on 2nd April the Bishop’s Castle earthquake (magnitude 5.1) in the Welsh borders was felt strongly across the region.
Two swarms of earthquakes became active in February 1995. Initial activity was located between Wolstanton and Cobridge and started with a magnitude 2.5 earthquake on 20th February with six felt events and 108 recorded at Keele in a week. Activity decreased after the 26th April 1995 magnitude 1.4 event but recommenced in May 1966 with a series of four earthquakes including a felt magnitude 2.8 on 6th May.
A second swarm became active two days after the first on 22nd February 1995 located south of Newcastle-under-Lyme with an initial event of magnitude 2.3. Five events at sporadic intervals were felt. Events in this second area show typical characteristics of mining induced earthquakes with a clear rise in activity during the working week and a decrease at weekends. There was a period of quiesence after the magnitude 2.3 event suggesting that this had released a significant amount of the local stress, sufficient to halt local activity for a week.
Also felt in Staffordshire during this period was a magnitude 3.4 earthquake near Shrewsbury on 7th March 1996
Activity in the area south of Newcastle-under-Lyme, between Whitmore and Keele recommenced between October 1997 and April 1998 with numerous felt events, the largest being around magnitude 2. Activity largely ceased in this area towards the end of 1998 with the closing of the Silverdale Colliery. An earthquake of magnitude 2.8 occurred on September 7, 1999 about 1.5 km southwest of the previous mining induced events and a magnitude 2.4 occurred in the same Whitmore Wood area on October 2, 1999.
On the 2nd January 1996 two tremors struck Kidsgrove, the latter causing minor damage. There was also a magnitude 2.8 event on May 6, 1996 in Cobridge that was felt across North Staffordshire. Further Cobridge earthquakes happened on August 9, 1998 and February 24, 2000 (1.7 magnitude).
February 22 to March 10, 2003 saw a series of six earthquakes near Whitmore with magnitudes between 1.3 and 2.3. The last earthquakes prior to the recent Christmas 2009 events occurred in the Wolstanton-Cobridge area on June 8, 2005 with a magnitude of 2.6.
The Dudley (September 22, 2002) and Market Rasen (February 27, 2008) were felt in the region.
Reference: Recent Seismicity in the Stoke-on-Trent Area, Staffordshire. British Geological Survey Technical Report WL/97/27 1997. J.H. Lovell, P.H.O. Henni & G.D. Ford (BGS), C. Baker, I.G. Stimpson & W. Pettitt (Keele University)