Opal Mining Newsletter January-30, 2005 on Mining Underground for Opals in Coober Pedy

Well here we are in a New Year, what will it bring everybody, only time will tell, for me I hope it will be a good year but will not know until it is over, but never know we may strike a good pocket early in the year.

Here we are starting a new drive the one that I will be trying to get up to the next level, the drive to the right is the drive was supposed to go up to the level above, but if you remember I found that bit of opal and changed to driving the machine on the level, was a waste of time as I found no other opal or material in the rest of the drive and stopped the drive some 16 feet short of the shaft, also I was in wet ground.

Now we are making some headway and the angle for now is perfect, not hard to learn this, just takes time and diesel, you can see that I am loosing oil behind the machine, it is coming from the oil breather cap, I made a mistake of topping up the hydraulic oil before I started this drive and it would seem that as the oil gets hot it expands, which I did not know, do now, it will level itself out and I will have to remember this as the oil is not cheap to buy and that is money on the floor.

This is what happens when the wind is blowing the wrong way, I can work the machine with the wind like this as it is not right up the behind of the blower, but as you can see it makes a mess of the truck and puts this fine dirt all over the ground and around the shafts at the top so when the wind blows from another direction it blows it down the shafts, not that bothers me except for when I am coming up, it is like rain coming down so I must not look up or I will get the dust in the eyes.

Now we are well in, but I have started to go up a bit higher and I have also hit a hard band in the face, (concrete) took me 3 days to get through it, turns out is was about 6 to 7 feet thick and when you only are getting less than 3 feet in 3 hours it is very slow going, this also made me go up at a bit steeper angle that I wanted, here I am about 9 foot up as far as I can recon, but there is no sign of a change of ground or level as yet.

This is the face not long after I had broken though the hard band, all clean sandstone, what we are looking for is what we call a change of ground, that is where there is 2 types of ground in front of you, 2 different colors, if we are lucky there will be a ironstone level, but I know there is none here on this level above me as I did not cut one in the shafts when they were drilled, but as there is a fault just before the shaft I expect to see one on the other side of it, a level was a sea bed millions of years ago.

Well here we are starting a new drive, had enough of the one going up, so for the time being I have given it way, if I go back to it after I came back from holidays I will have to change the angle of the drive about half way up, one day I will get used to it, but right now I want to try and find some opal and so stay on this level, the drive on the right is the drive I was in before I stared the drive to the right going up, it is the drive that had all of the potch in the wall and still some in the face.

So this is the new drive, when I have gone in a feet more feet I will turn the machine to the right so I will leave a pillar about 2 foot thick and then run parallel along side of it, I recon that I should be on material within the next 4 to 6 feet or so, I will also have to show you how I modified the seat so it can be taken off in about 5 seconds, when I go on holidays I will be looking for a couple of second hand bar stools, as I want the round seats off them, then I can change the seat itself, better for me if I have a round set to get on and off with for ease and we cannot buy then here.

Also forgot to mention that I lost the tip off a tooth on the outside cutter on all of that gypsum & concrete in the last drive going up, so I am cutting with 7 teeth and at the moment it seems to be cutting alright, as I am going on holidays at the end of this month and the fact that I have to take off the inside cutter and hub and take it with me to Queensland where I will get a couple of new plates made while I am fishing, I will also take the outside cutter off and bring it up and fix it when I get back as I will have to put some teeth on this new plate to make a cutting head out of it.

Here I have not gone in that far and the level has come back in and settled down and I have struck some potch (material) in the middle.

Well I had to give that drive above away after a few more feet as the ground was getting wetter and was getting very hard to pull the dirt without having problems, so as I was not finding anything and no material was in the level I decided to quit and bring the machine back to the elbow and turn it around to go in the old hand mining drive.

This drive is about 48 foot long and I had left this drive because I was buying the tunnel machine and so would finish it with the machine when I was ready and now I will start to clean it out as there is some on the old dump left in front of me right now.

Where I am now is at a cross roads, as I did a shot to the right (4 foot) where I found colored trace, but I left most of the dirt in there and I did 2 shots (8 foot) to the left where I also found some colored trace and some potch and I left some dirt in there as well, this crossroads in in the middle of 2 faults that are not that far apart and I will have to do a drive straight between them down the middle when this drive is down at some stage and at the end of the drive I am in now I also left the shot dirt in there at the end as I though it would be easier to remove with the machine, but I was wrong.

The big pieces do not get cut up with the cutters, but thrown to one side as the head goes around and as the big lumps here are very hard as they are from the roof which is made up of Alanite, Gypsum and Concrete compressed together, so I have to move them by hand into the drive on the left, later on I will have to move then again or break them up with the electric jackpick and put then up top like I used to, by hand and shovel, just take the pipes off the back of the machine when it is just past the drive on the left.

I have reached the point where I have to start cutting in the wall, but I am only going to be cutting half a face and half of the old dump which has some of there lumps in it, but will move them as they become free, so here I have finished for the day, it has taken me 3 1/4 hours to clean this out (38 feet) and get to where I can start driving a new tunnel.

Now we are going forward, you can see the old hand dirt on the left, I went a bit further than this and had done 10 1/2 feet when I knocked off for the day, I am near a fault in front of me so the ground here is unsettled and the level is all over the place and it will not settle down again until I am past it, the ground in between these 2 faults at the point is all the same, messed up, there is not enough distance between them for the ground to get settled, so I have no idea if it is like this to the left (down the middle of them) until I do a drive but as the level dives to the left, if it does settle down to a normal level I should find some opal here, as I have already got some good trace here.

Where the arrow is the roof was a bit loose there on the corner when the machine was cutting under it and as it did not fall off as I was cutting it I was afraid that it may fall at some stage as I was under it so I had to stop the machine and bring it back, then knock it down with the hand pick until it was solid and not loose any more, then go to the front of the machine and move the pieces by hand and throw then in the drive on the left with the rest, now I can continue the drive is safety.

This is the face as I pulled the machine back to take the cutters off, I am near and going past a fault above me, I don't know how much further I have to go before the level returns back to normal, but the level here has reached the top of the roof, that white stuff across the face is Alanite but hard, but looks good for a photo, just shows you haw the ground is always on the change and as the major slide (big fault) in on my right it shows you how the level dives down from it, the ironstone level itself is not quite this severe in angle, in actual fact the arrow on the right is not on the level, this is what we call a squibie level (false level) at times will produce opal, but not here at the moment.

I have brought the machine back to the crossroads so to speak, so I can round the front of the machine with some ease now I will take the cutters off and bring then back, I will take the cutter on the right with me to Queensland and get a new plate cut and machined up there while I am on holidays, this will save a few days here when I come back, as there is no rush while I am up there to get it made.

This cutter if you remember the photos of it when I put new teeth on it has 3 arms, instead of being completely round, why the guy who built this machine did this I have no idea, but it is a bad design, as I am cutting the face and if the dirt is just sandstone is cuts just fine, but as soon as any hard stuff comes in, alanite, gypsum etc, it chatters and vibrates the cutting head and does not cut properly and some times even jams on gypsum because there is to much of a gap between the teeth and the bite is too big so they are not cutting smoothly or evenly, this I will have to fix or I will damage the shaft on the hydraulic motor as it was when I got the machine and that cost me $905.00 to fix, so we don't want that to happen again in the short term

So I will get a new plate done and will put 8 teeth on it and try it like that, I could put 6 on it, but this cutter is larger in diameter that the outside on and covers a large area including above the level, where some of this problem comes from as for the most part this is nearly always some gypsum above the level and if I put 6 on there still may be a bit to much gap, but as this is not being done until I get back here I will worry about that when I have to put then on, but I think at this stage it will be 8.

Well this is the last bit of mining for me for a couple of months as we are off on Monday morning for Queensland for out fishing holidays, we will be gone for 9 weeks including traveling time which without any on-road problems is 3 days each way, so we will have 8 weeks to wind down before we have to come back here and do the hard grind again for the next 10 months.

At this stage, I do not know if I will send out a newsletter like last year while we are up there, but again I will play this by ear, there may be some of you that would like to see what we get up to and some of the scenery and some of you may not, but as I have to spend a lot of time to do this letter, I do want subscribers to enjoy what they read and see so I know that I have now wasted my time.

Hope you have enjoyed this issue and look forward to the next one, hopefully we will have caught a few good fish and a fisherman always likes to brag about fish they have caught, But normally it Patricia who gets the big or unusual ones.........

Stay Tuned for the next Issue, who knows what I will have to report.

Until the next issue.........

and wish me lots of LUCK.

Cya Later, Stuart Bird.

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