A Rig (or Two) and a Prayer

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It’s not often we have two of our rigs working on the same site together, but this week we needed to do just that.
Our client had originally requested a plate bearing test to determine the bearing capacity of the underlying geology for a new extension to their mosque.
We advised that a plate bearing tests was not the right test. Instead , using our Geoprobe DirectPush and Terrier percussive drill rigs, we were able to complete soil sampling, dynamic probing and SPTs in the chalk underlying the site. These data then allowed us calculate the ultimate bearing capacity for future foundation design.

If This Doesn’t take the Daffodil….

A recent project in Wales saw us drilling through Coal Measures. We encountered mudstone, ironstone, siltstone, sandstone, claystone and, of course, coal….all in a single day. This didn’t stop us achieving 100% core recovery and 20m+ coring a day, all with full gas monitoring.

For more information or to get a quote for us to drill your site (it doesn’t have to be in Wales!) please contact Angus Gale – 0774 8358304

Hedging Your Bets?

Can You Spot Our Drill Rig?

When a client rang and said they needed boreholes in a densely overgrown area, located up a high-sided kerb behind some hedges, we knew we had just the drill rig for the job. After checking for below-ground utilities, we completed seven boreholes locations to 4m depth in a single day. Naturally, we left the site clean and tidy, with a happy client.

Hollow Stem Augers

Up Close and Personal – The Business End of a Hollow Stem Auger

The site investigation industry has, traditionally, relied on light cable percussion (generally known as shell and auger) drilling. This is slow, messy and crude providing low quality geotechnical and environmental samples at best. Thankfully, these days it isn’t the only option available to you.
The majority of our general site investigation drilling is done using hollow stem rotary methods. These provide signficantly better quality data with minimal sample disturbance, even in the toughest of conditions. This week we were working at a site underlain by glacial and millstone grit cobbles, sand and terrace gravels in a sandy clay matrix.  We drilled five boreholes to their target depth on 8m in one working day – something that might have taken a shell and auger crew a week – minimising the disruption to our client’s business which was able to remain open throughout.

Why Coring Isn’t Boring

Core Bit

It probably comes as no surprise that it takes a very different skillset and completely different equipment to core through rock as opposed to boring through the sand and clay soils that are more commen near the ground surface.

The correct core bit (i.e. the part of the drill string which cuts the rock) selection is the key to obtaining high quality quality core samples. Each rock type requires a specific core bit to cut it cleanly and efficiently. So, to achieve the best results, we carry a range of different core bits with us at all times. Our drilling crew recently used our T6 coring barrel to core to depths of 25m in a range of geology from conglomerates to slate and everything in between.

So, you might say that coring is not boring. Fact!

You Never Know….

Buried Services

…what lies beneath your feet. But when it comes to carrying out any form of ground investigation or excavation work, it’s imperative to find out whether there are any buried pipes or cables before you start work.

We provide consultants and contractors with the information they require, whether it’s a complete set of public utility drawings or a remote sensing survey using radio detection and ground probing radar.

For more information, please contact Angus Gale – 01296 739333

When Your Protection Fails….

Overdrilling CP

Not that kind of protection! We’re talking about cathodic protection of fuel pipes and tanks.

Decommissioning and replacing defunct cathodic protection ground beds requires an element of precision and brute force. Our first job is usually locating the existing beds. This can be no small task on a 30 hectare oil terminal site! The redundant beds were installed over 30 years ago and records are sparse.

We used radio detection methods to accurately locate the old redundant vertical ground beds to the required accuracy of +/-50mm. We need to be that accurate in order to successfully overdrill the beds.
Unusually, on our most recent project, our client asked us to drill through the connecting cables rather than removing them. The cables were isolated by a field engineer prior to us starting work and all our works were carried out under a permit to dig.
To overdrill the existing beds we brought in a shell and auger rig, drilling 350mm boreholes to 5m depth. This effectively decommissioned the existing redundant ground beds to make way for the new ones. With the first stage of the project complete, we are now back on site with our Comacchio rotary rig drilling much deeper boreholes in which we will be installing new anodes. Updates to follow.

Where There’s Muck There’s Brass

Last week we undertook window sampling and installed monitoring wells at one of the largest recycling processing depots in the UK. Have you ever wondered what happens to your recycling after it gets taken away? Well it will likely end up at a processing centre similar to this one, where the waste is separated, segregated and prepared for recycling.
It was eye opening to see the scale of the operation. Usually when we drill, our rig is one of the bigger vehicles on site, but this time our van mounted Geoprobe was dwarfed by some of the other machines on site.

Heathrow Third Runway

Night Working at Heathrow

OK so we can’t say whether this will (or should) get the final go ahead from government. But what we can say with absolute confidence is that we have more experience of working airside at Heathrow than any other geo-environmental consultant.

We are the only consultant with permanent airside passes, both for our staff and our vehicles. We are also well versed in navigating our way through the airport’s complicated permiting system.

Just last week one of our investigation teams worked through the night to install several deep monitoring wells adjacent to one of the existing runways. The third runway will need thousands of similar geotechnical borehole drilling in the next few years. We believe that having an airside presence and an in depth knowledge of the geology gives us a head start when it comes to providing this service.

For more information please contact James Skinner – 01296 739411

 

Cathodic Protection

Installing Cathodic Protection

Drilling large diameter boreholes at a brownfield site to install anodes for a cathodic protection system requires a rather eclectic combination of skills.

Working in a tight space, to a detailed specification, we achieved an anode installation through a complex sequence of geological strata. Clean drilling techniques required us to install an environmental seal through surficial gravels and 30m into underlying clay. We then extended the boreholes through 20m of Thanet sands and 10m of flinty chalk. To complete the anode installation we then tremmied sacrificial coke contact media into the borehole’s response zone with the remainder of the boreholes being grouted back to the surface with bentonite.

Our team consisted of drillers, environmental engineers, mud technicians and cathodic protection engineers, all working together on a busy site to ensure the client got the installation required whilst working within the Environment Agency guidelines.  The anodes will now ensure the pipelines are protected for the next 100 years.

If you’d like to know more or if you have an installation requiring cathodic protection be installed then please contact Angus Gale – 01296739433