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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