Hey everyone, I have special guests with me today, this is Paul, say hi Paul
hi Paul
-and Nat -hi
-or Natalie, what do you prefer? -Nat
Okay, and we're at the Cliff Mine, and they're both geologists and I'm not, so
they're going to be the expertise this time instead of me just wandering around
not knowing what the heck I'm talking about
so let's go!
(Rob) Okay, we've got finds already (Nat) So these are some of the minerals
that you can find at Cliff Mine, there's this light pinkish colored one, which
is Laumontite, then we have this white mineral, that's Calcite, and it's surrounded
by some of that pinkish Laumontite
here is some tiny little Greenstones
and
this kind of pale green color, that's Prehnite
and sometimes in the Prehnite, if you're really really lucky, you can find copper
and silver
and then last but not least, what they were actually mining here, this right
there is a small piece of copper
(Rob) Now I always see the copper because it kind of sticks out and looks like it
should be broken off, but isn't. Is that- what do you look for?
(Nat) I look for the colors that are in there, because when these have been
sitting in the rock pile for so long, they tend to get this greenish patina on them,
and so I hone my eye to look for that color (Rob) Oh okay
cool, thanks!
(metal detector beeping)
(Nat) Maybe it's a good find. (Paul) Maybe it's a good find!
(Paul) Well sit your bucket down there, Michigan Rocks
(Rob) [Laughing] (Paul) Here you go!
I'll look important, there we go. (Rob) What you got?
So, with the metal detector we found this little piece here, and all that green on
there should be copper, I can run my finger over this, this edge right here
and I can feel copper sticking out, and if I use the metal detector
(metal detector beeping)
that tells me there's copper in that
(Rob) Cool! Is it heavy?
Um, not super heavy, so there's probably not a lot in there, but I can feel, run
my finger over this little tip right here, it's trying to cut me.
(Rob) Okay (Paul) And I can tell that's probably copper
so if this was cleaned up in a bit of muriatic or sulphamic acid, it'd
probably clean right up nice. (Rob) Cool!
so we got a - got a hit here
(metal detector beeping)
(Paul) right there somewhere (Rob) gotcha
see what we got here. I don't think it sounds real deep, so
(metal detector beeping) oh yeah, we got something there
(Rob) dig a little bit? (Paul) yup, we've got something there
see if we can spot it
(metal detector beeping) right there
(Rob) alright, so I dont' know what I'm looking for
(Paul) well let's see
(metal detector beeping) (Paul) I think we've got something good there
I do believe
(Rob) nope, that one's light
(Rob) did we move it? (Paul) oh yeah, we moved it now
(Rob) look over here
(metal detector beeping)
(Paul) okay
(metal detector beeping)
(Nat) oh I think I just decapitated you, Paul
[laughter]
(Paul) the wish of every spouse, right?
(metal detector beeping)
(Paul) aha! (Rob) that's it?
(metal detector beeping)
it's really really dirty, so you'll have to clean it up
but if you feel that, it feels a little- (Rob) oh yeah
(Paul) a little heft to it? (Rob) yeah definitely
(Paul) there you go, there's your copper (Rob) cool!
(Paul) clean those up, because in this pile those could have silver in them
(Paul) in this pile (Rob) oh that's - that'd be awesome
(Paul) it would be! (Rob) you ever find any, what do they call
them, half-breeds here? (Paul) oh yeah, all the time
(Rob) cool (Paul) you can find them here, so
(Rob) That'd be copper and silver together (Paul) copper and silver mixed together,
right
so go ahead and clean that up and you'll see what you got later
(Rob) cool, thanks!
Mr. Rob wants to know how the copper got here
so
Cliff Mines sits on what is called a fissure vein. Fissure veins cross-cut all
of the rest of the rocks that are up here. Where most of the rocks, especially in
this part kind of go east-west, these fissure veins run almost north-south, so
really perpendicular to the flows up here and this particular mine here operated
from I think 1844 until 1880-something, like '85, I didn't get the exact date
but, what they would do, in this mine they would find these huge masses of copper
a couple hundred pounds, sometimes up to a few tons
and in order to get something like that out of the ground, the miners have
to go in with hand chisels, and only using candlelight for lighting underground, and
chop these pieces of copper up with hand chisels
in the process, they would create numerous amounts of what are called copper chisel
chips, and those are just the pieces that come off from the main - big mass pieces
of copper, they didn't really save, and they just put them out in the pile here,
so now today, with a really good metal detector, you can find these copper
chisel chips, and they can range from anywheres from, at this pile, from maybe
a half-inch, inch long up to I've heard of some as much as 20 inches long coming
out of this pile, so very large chisel chips (Rob) that's cool
and so, yeah, it's just - just the way that they mined, now Rob and I just
talked about how the miners also would find it after they would go in and blast,
and it's an old saying called "feeling for fish hooks"
so after they would blast, and again they're doing this all by candle light
the miners would actually go and take their hands and feel along the walls to see how
much copper was protruding out of the walls after they'd blast, and if they found
a lot of copper by feeling the walls, then they'd explore more. If not, they
would just move on
alright, so again, Mr. Rob wants to know how this mine was found
so, the original mine up here, the first- basically first major mining attempt
up here was at the Hays Mine near Fort Wilkins, and it was done by the Pittsburgh
and Boston mining company in 1844
however, they did not find a lot of copper there, so after a few months it was
pretty much abandoned. But the company was doing a lot of exploration work along
the Keweenaw, and how they found Cliff Mine, one of their exploration geologists was
hiking up along the ridge that's behind Rob right now, the guy slipped and fell
down the side of the mountain here, the hillside, but as he was sliding down
let's just say his backside was getting tore up by pieces of copper sticking out
of the ground
and it tore up his overalls, tore up his pants, and he went back up the
mountain to see what had happened, and there were literally pieces of copper
sticking out of the ground
it's a wonder the poor guy didn't bleed to death, because of all the copper that
he had slid down
but that's how they found Cliff Mine, and then the next
spring after winter they came back here, explored and hit huge veins of copper
here, thus starting this Cliff Mine. (Rob) and this is the oldest mine here,
(Rob) right? this is the oldest profitable mine
on the Keweenaw. Remember, Hays Mine was first, up at Fort Wilkins, that was the
first attempt by Europeans. (Rob) Okay, and they actually did find
(Rob) copper there. they found some copper there, but not
enough to make it - to support it. It was the wrong kind of copper, shall we say.
(Rob) oh okay okay?
(Rob) cool!
(Rob) alright, we're going to get a little lesson on Greenstones
So Greenstone, which is right here
you'll notice it's a nice rich green color and it has a little bit of a pattern to it
now unfortunately, in many places where you can find Greenstones, you can also
find a mineral called Chlorite, which is also green
here's some of the Chlorite. Now Chlorite is usually darker and it's also quite soft
and it doesn't tend to have that same pattern that you'll see in the Greenstones
(Rob) it's fun to have geologists along with me, this is awesome! [laughs]
(Rob) I'm having a ball!
(Rob) alright, Paul just found a chisel chip, so check this out
(Paul) So what we've got here is a, one of the famous Cliff Mine chisel chips
and I know it's a chisel chip, because on the backside here you can see this smooth
edge here, this is where the miners would have taken their chisel and as they were
breaking up those large pieces of mass copper, these basically chisel chips were
being formed as they were trying to cut them up. Now again, this is a - this is a
pretty small one for here, this one's only about an inch or so long
but again I've seen them here as much as 20, 24 inches long, looking like this
so really a neat - neat history lesson here, neat artifact.
(Rob) So what did you say about the wrinkled part there?
(Paul) So the wrinkled part here, as the miners were chiseling into this,
it's basically crinkling up or kind of shortening a bit, as they're pounding
this in, as they're trying to cut it with their chisel, and as they do, the topside
here gets kind of this wrinkly surface on it
but the bottom side is smooth, that's where they ran their chisel
like my Einstein hair here (Rob) it's windy!
so we have a different mineral here now, yet another green mineral, but notice
this very apple green color there, that is the mineral Epidote. And that's another
common Keweenaw mineral (Rob) I find lots of that on the beaches
it tumbles really nicely, but I wouldn't recognize it in a mine pile
(Nat) Yeah, you also find it sometimes in granites, you can get Epidotized granites
Epidote preferentially replaces some of the feldspars in granite, so you get
these weird like pink and green rocks sometimes
(Rob) Unakite! (Nat) yeah, exactly!
(Rob) that's one of my favorite rocks (Nat) wow, lovely! Well, this is the mineral
that helps make those rocks pretty.
alright, we've just changed locations, so I'll let Paul tell you where we are
so we currently moved to the Northwestern Mine, which is near Central
this is again one of the older fissure mines up here, so they work a fissure
vein for copper
basically organized about 1848, ran until about 1865 when they were absorbed by
the Central Mining Company, which is just down the road here a little bit
pulled about 313,000 pounds of copper out of here, and you can find things like copper
but the pile is really known for it's Greenstone, Lake -
or Isle Royale Greenstones here, you can find some pretty decent ones here, so
that's what we're going to do now
(Rob) let's do it! (Paul) let's do it!
so what we're looking at here are called Slickensides. That's these polished surfaces
of the rock, they form when you have movement on a fault, and as the rocks
slide against each other they polish each other creating the slickensides
(Rob) wow, that's really neat
(Rob) okay, I just picked up a rock and asked Paul what it is
(Paul) so what Rob picked up was something called Adularia, it is a variety of
Microcline Feldspar, and it is found up here in the Peninsula - in the Keweenaw
Peninsula, how a lot of people confuse this with Laumontite. However, Laumontite
is more
it's more of a cream color, it's kind of a pinkish-cream color, and also Laumontite
would form more needles, and it'd be very very crumbly
and so this Adularia is not near as crumbly, it's a little harder
and can be very pretty, especially if you get it included in things like calcite
or quartz.
(Rob) okay, we're talking about the orange stuff, just to be clear (laughs)
(Paul) Yeah, it's the orange stuff, orangish-red stuff here, right
(Rob) alright, so what are we learning? (Nat) So, we're learning the difference
between Laumontite and Adularia. So the Feldspar Adularia is a little darker color
and it is a lot harder and resistant to weathering and erosion
and over here, that's our Laumontite, and you'll notice it's a little lighter colored
it has these sort of needle-like crystals, and it's very easily broken apart, and so
that's an easy way to tell the difference between Adularia and Laumontite
(Rob) so last year I found some big chunks of that, that - I think Laumontite, it was
like chalk almost, is that the stuff? (Nat) yes
(Rob) okay
I don't know if it's actually going to break but we'll see what I can do
(Rob) Dr. Nat's getting serious
ooh, a piece broke off!
(Rob) you sound surprised, but wasn't that the goal?
(laughter) it was
and there's no Greenstones. (Rob) oh
a lot of work for not a lot of payoff. (Rob) well it was fun to watch you
(Rob) smash something though sometimes that feels good too (laughter)
Well that's it for today, so thanks to Paul and Nat for teaching me and everybody
else a bunch of stuff. If you want to see more of the Cliff Mine, I did a video there
showing some of the ruins last summer, so you can look at the video there in
the aside, and I'll see you next time!