Mining at the Orchard and GE Quarries
Oxford County, Maine

Coromoto Minerals
The 2000 Season  at the Orchard Mine

2000 Topics:
Retro-'99
Housekeeping
Back in the Hole again!
May 18-20 Pockets
Orchard Pegmatite Diagrams April-June 2000


Retro of ’99

It is safe to say that all participants at the Orchard Pit-now Orchard Mine-went into the 2000 season wondering whether it could ever measure up to ’99. The Golden Beryl Pocket exceeded all expectations. Discovered in July, it was the high point. Although extensive work was done later in ’99, the remainder of the season was anti-climatic. Yes we did hit pockets but as most often occurs, their contents had long since been converted to some less glamorous and much less conspicuous mineral. Bertrandites and acicular phenakites were the only obvious descendents. We had our antennae on long range for other beryllium minerals, but if there,we did not find them. As we mined, the good part of the Orchard 
pegmatite appeared to be descending and tilting even more. We could see that the mineralization looked promising at the bottom of our current dig. Very coarse microclines to 2 meters were showing up cemented together by smoky quartz. Under these large etched out  pockets  continued into the floor beyond our reach. 

So as we got the actual business of mining in April, logistical considerations ( how do we get our dump truck in and out of the hole along a steep grade) as well as the lure of the ’98 phenakite pockets caused us to reverse course and mine from the back towards the entrance. In so doing we discovered little except  for massive quartz pods (the core?) and the occasional smoky quartz crystal-apatite pocket. It was our unspoken hope…no we talked about it...that perhaps as we got under the ‘beryl layer’ some lithium minerals would appear. None did.  Lithium is an essential ingredient of colored tourmalines and if we are to find them at the Orchard,we will need some.  The blue and green beryls (colored by iron) would have to give way to the colorless variety (alkali beryls) as well.  What we did discover through this execise is that it is a lot more difficult to mine with the excavator on the opposite side of the bench from the blasted material and up grade. After a while we developed a satisfactory technique for working in this awkward configuration. 

Housekeeping

If we were to do more mining in the promising zone at the bottom, for safety as well as for excavation considerations, we would have to widen the pit. The southern hanging wall was now almost 40’ high. Standing at the bottom looking up ‘hanging’ seemed to a an appropriate term…maybe ‘hanging ready to drop’ was more the sensation. Even though we were only a foot or two under the farthest projection of the wall, the feeling was uncomfortable. Widening the pit however is no mean task. Starting 8’ back from the edge, the wall was dropped about 12’. From that level the wall was cut back 4’ down to the bottom. We also extended the pit back about 8’ towards the road in a series of 8’ benches.  This exercise filled the pit with schist and other rock of no interest whatsoever. If you are going to mine what goes in must come out, so we set to work digging out the pit. 
 
 
 

 

The two essential ingredients necessary to excavate our pit are the dump truck and the track-avator, a small Komatsu PC-60. The Komatsu is our workhorse and as the mine gets larger the PC-60 seems to shrink. Paying heed to the adage ‘an ounce of prevention..’, I had sent the machine down to R.C. Hazelton in Cumberland Maine for a routine Spring checkup.

 “Yes-sir, it’s a fine machine and for just $5700 will set her right back to running order and can I show you the new models that just came in”.

This is why I avoid Doctors. The damn thing was running fine before the ‘ounce of prevention’.  I settled for a $2400 mini-make over ‘cure’. The machine was returned to the mine and after about 3 hours use the bucket linkages fell off and were bent in the process. It seems that Hazelton had not used locking nuts when they re-installed bucket. Heh..what do you expect for $2400? A local shop flattened out the links but its seems that we tore the ear off of one side of the bucket as well. It would take more than Viagra to get this thing digging again.  So with an enormous pile of junk rock sitting on the Mother-lode, the only alternative for making immediate progress was to pony up some more dough and rent an excavator. A new John Deere 110 was delivered to the pit. A larger machine with all the creature comforts- stereo/air conditioner/a seat with upholstery still on it. Doug enjoyed it! We used this one for about a day and then we threw the track off. We had already experienced the ‘right of passage’ in this department with the PC-60 having had to re-install the track several times. The secret is to let the grease out of the tensioners. Without this knowledge it is a conundrum worthy of the best. The JD added a slight nuance to this drill however. In the process we managed to do the dreaded THING and throw the track off of the drive sprockets.  Although I have daily experience putting undersized belts on oversized objects, it took us 3 hours to K-Y the track back on.

After 10 days of blasting and clean-up we were back in position to where we could actually see the bottom again. We did a small bench into the back wall exposing interesting mineralization and lots of green beryl from a quartz pod. Time had run out on this trip and 3 weeks in China and the Maine Mineral Symposium were looming forebodingly ahead before our group would be back to the Orchard Mine

 

Go to "May Pockets"

Orchard Pegmatite Diagrams April-June 2000


 

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