Oxford County, Maine
Coromoto Minerals
The 2002 Season at the Orchard
Mine
---- November -----
35 cm Quartz Crystal Group on Feldspar
Coromoto Minerals
The 2002 Season at the Orchard
Mine
---- November -----
35 cm Quartz Crystal Group on Feldspar
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By the end of October we had driven the pit floor to depth and flush up against the headwall. There was no more easy pickings as the headwall was now an imposing shear vertical 70'. Although the headwall was pegmatite from top to bottom, only the 20-25' below the schist bulge seemed to be hot. True, the upper 50' contained blue beryl and fine rose quartz there was no pocketing to speak of until the schist feature was reached. Taking down the headwall to reach more of the lower course of the pegmatite was becoming increasingly difficult and hazardous. Time was against us as well. October and November were proving to be colder than average and much colder than the last 3 years. Once the icicles started to last through the day and build over night our season would be over. It would be just to much of a risk to work under these massive pendants. At this point we decided to try our hand at starting an adit. To do this we would need a jack leg and special hammer. A jack leg is simply and air operated cylinder that lifts the hammer to drive a hole into a horizontal working face. In addition it applies pressure against the hammer. When properly positioned and adjusted the jack leg and hammer will nearly work on their own. When not properly adjusted, no amount of brute force can control it and it seems to consider fingers as hors d'oeuvres. As a training exercise to master this device, we decided  to
drill a hole in the side wall of the pit. After a little while wrestling
with it we felt like we were ready. Working from the back of the
dump truck backed against the headwall, we proceeded to start an adit just
under the schist bulge visible at the top of the photo.(The hole visible
at the bottom is a pocket) After consulting the 'Blasters Handbook'
, we marked out our pattern and got down the the hard work of drilling.
After a days time we had driven (14) 6' holes. Naively we loaded all 14.
We are always sensitive to making noise with our shots so it was with trepidation
we prepared to fire this round. Our concerns were well placed. Out
1st effort at driving the adit resulted into what turned out to be a 14
barrel cannon salvo that echoed thunderously from the low overcast
sky. A generous assessment was that we had driven our adit 3 inches
deep. Even though, as per the handbook, we had properly spaced our
holes and correctly chosen our detonator delays, the center did not
pull. Without this relief, the rest of the holes were just noise makers.
After this fiasco, we scaled back our loading to just the center (4) holes.
These (4) holes are positioned around (2) relief holes that are not loaded
and are intended to provide a space into which the breaking rock from the
4 loaded holes can expand. Our second try, although again noisy,
was much better. We were left with something resembling to a 6' deep by
2' diameter large colon and a 4'' diameter.....shall we say.....anullus
at the front. More learning.... It seems to avoid this we have
to load the holes right to the top with a minimum of stemming. So
after several more rounds we had a passable adit started that was 6' deep
12' wide with a decent looking overhead arch. There was sufficient overhead
room to stand up in the cavity. Now we were setup to do some ' underhand
stoping'. This is miner speak for benching from below. This is what we
had been doing all along except that now there was 50' of rock above our
heads.
While opening the adit, each round exposed more green beryl. Due to
the close spacing of the holes , the rock and everything in it had been
reduced to dust or at most small chips. The good news though was we could
easily muck out the hole with our 2" pump's powerful stream of water. As
we had driven the initial part of the hole into less interesting mineralization,
we were not too concerned by the pulverization. We were however fast running
out of time. It was Tuesday and on Friday I was leaving for a trade |
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show in Dusseldorf. We drilled a series of (4) 4' holes 3' back across
the front face of the floor of our newly opened adit. We decided to load
only the (2) center holes and very lightly at that. The shot exposed a
large mass of quartz at the bottom and threw out a number of large blue
beryl chunks. A beryl more than 5" across was embedded in the lower part
of the exposed quartz. This is the largest we have seen to date and seems
to confirm a trend towards increasingly larger crystallization. At
the bottom of the exposure, a black cavity in feldspar was slowing draining
water. The hole was perhaps 5" by 3" or just large enough to stick your
hand into. With a little chipping, we were able to enlarge it. Reaching
in we could not find the back even with the aide of our hoe handle.
This meant the cavity was at least 4' deep. It appeared that we had broken
into the top of this pocket. There was little to see as the pocket was
substantially beneath the surface of the water that still filled it. Darrell,
Richard and I took turns reaching into the icy November water trying to
find something of interest. Each attempt brought out another mass
of quartz crystals. The more than 1' long group at the top of the page
was one of the first to come out. The (2) groups at the bottom were some
of the better ones. We managed to fill (3) dynamite boxes before we could
no longer stand the cold ....and the bleeding. Although we found nothing
but quartz, the pocket is not nearly empty. We had just run out of time.
Interesting to me was, that unlike the pockets in front of this one, the
crystals were not coated with manganese or iron stains. Perhaps we may
be getting near some pockets that may still have some beryls. Judging by
the very large size of the beryls in the quartz just inches away from this
pocket, if they are in there, they will be noticeable. Now we just have
to wait for Spring.