Tuesday, 9 September 2014

Day 2 - Rig Engineering and Lava Flows Fight Back!

Today’s work began with the bone shaking drive to the caldera.

A planned visit to well MW-09. The well supervisor Bennett came to meet us at the security gate, where he and second in command Edward were very happy answering questions about the engineering of the rigs that support the drills, enquiries about issues that have arisen and lessons learnt from the early days of drilling.

With Bennett, Well MW-09 Supervisor

The boreholes are drilled to a depth of 1->3km depending on factors such as lithology, hydrothermal alteration, temperatures, and engineering issues such as loss of circulation and the drill string getting stuck. The sticking of the drill string is usually associated with the presence of clay. It has been noted at some of the boreholes that the clays contain smectite. An expanding clay mineral that with the addition of water to the borehole to aid lubrication, exacerbates the swelling and causes a clogging of the drill bit. Bennett explained that with the aid of work by the geologists, they know what depths such horizons occur and can adjust the drill speed accordingly. But as we saw, the drill string sometimes gets stuck regardless how careful the drillers are. It wouldn't be the first time a drill string has got so stuck drilling at a location has been abandoned and the drill string left where it is.
Despite being fully aware that there is a magma chamber relatively close to the surface, I was surprised to hear that at well MW-12, drilling hit hot magma. This was a very insightful morning’s work.

Well MW-09

Bennett explaining some of the finer details to me

The afternoon I started to sample some of the young lavas found on the caldera floor. Challenging is putting it mildly. Despite these lavas being of a flow, the very blocky nature of the deposits along with deep fissures, made traversing the lavas close to impossible. 

A very deep fissure in the lavas towards the south east corner

In situ samples were collected from near track ways which made access easier. However, sampling was further impeded by the hardness of the basalts. A hammer and hard rocks is very therapeutic. Observations were also made on the sheer amount of obsidian and pitchstone present in the area.

'Flow' in Obsidian

Tomorrow it's off to Sleeping Warrior! Lala Salama from Kenya!

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