Pit Problems

I received yesterday and have not heard any more. They are expecting it to slide today or tomorrow It’s been moving 3 FT per day for the last week.

YIKES!! I guess everything with copper in it is going up 500%

I do not know if this is a old pit on mine site or not, waiting to hear back from my friend there.

It's not so unusual. I can recall major pit wall sloughs at Bingham Canyon and Freeport Grasberg, and likely hundreds of minor ones over the years. Mine designers try to improve pit profitability (less overburden to remove per tonne of ore) by steepening the pit walls almost to the point of slope failure. Sometimes nature comes back and bites them. The Bingham Canyon failure was captured on video. https://www.mining.com/bingham-canyon-mine-slope-failure-37216/ The Freeport one is not so well documented on the web because of Freeport McMoran's fixation with secrecy. Photos do exist though, IIRC the material that sloughed at Grasberg was of something of the order of 50 million tonnes. Vetech63 said: YIKES!! I guess everything with copper in it is going up 500% Click to expand... Doubtful. All the other producers will lick their lips and up production.

Not a good time for them . This is the same mine that had the jack failure on the shovel they were undecking isnt it ?

Yes it is, the mine has brought or getting a third party in to do a investigation.

Nige said: It's not so unusual. I can recall major pit wall sloughs at Bingham Canyon and Freeport Grasberg, and likely hundreds of minor ones over the years. Mine designers try to improve pit profitability (less overburden to remove per tonne of ore) by steepening the pit walls almost to the point of slope failure. Sometimes nature comes back and bites them. The Bingham Canyon failure was captured on video. https://www.mining.com/bingham-canyon-mine-slope-failure-37216/ The Freeport one is not so well documented on the web because of Freeport McMoran's fixation with secrecy. Photos do exist though, IIRC the material that sloughed at Grasberg was of something of the order of 50 million tonnes. Doubtful. All the other producers will lick their lips and up production. Click to expand... The article you shared cites a HEF thread from 2013 as part of their sources. It cites this thread: https://www.heavyequipmentforums.co...kennecotts-bingham-canyon-mine-in-utah.35222/

As off 8:25 pm my time the big slide has not happened yet. They expect it tonight or tomorrow as movement was 2.5 meters or 7FT today. The circle section in Red is the slide area.

A bit of research reveals that both open pits at the Highland Valley operation have been suffering slope stability issues since the late 1970s, so I will hazard a guess that the situation is not going to be new to them. From a report that's over 10 years old......... https://www.tandfonline.com/doi/abs/10.1080/1389526042000263324?journalCode=nsme19

Partial slide at Highland Valley I understand there is or could be much more to slide yet.

The 2003 (I think) slough at Freeport Grasberg. About 50 million tonnes came down IIRC.

To give a better idea of the scale of what came down the bottom RH corner of the 2nd photo and the 3rd photo show parts of the same area. That's a 793 truck and I think a P&H 4100 shovel partly buried.

looking at how it flowed around the 4100, that stuff is fairly fine and fluid. Recovery must have been a nightmare if it was done at all on those pieces.

Pretty much everything that was "peripherally hit" was recovered and put back to work AFAIK. Not sure exactly how much machinery was completely buried under the slough. From memory it wasn't like Highland Valley where there is/was plenty of advance warning that the slough was coming giving time to evacuate machinery & personnel from the affected area.

Couple of interesting videos from Bingham Canyon. First one if I'd been the driller who put that hole pattern in I'd have been crapping myself thinking that my drill could have been on top of that lot..!! 2nd one is a time lapse of the 9-month process to dig through the bottom end of the slough and re-establish the haul road down to the bottom of the pit.

Nige said: Couple of interesting videos from Bingham Canyon. First one if I'd been the driller who put that hole pattern in I'd have been crapping myself thinking that my drill could have been on top of that lot..!! 2nd one is a time lapse of the 9-month process to dig through the bottom end of the slough and re-establish the haul road down to the bottom of the pit. Click to expand... Wow. Sounds like the makings of a great episode of "Seconds from Disaster"

"driller puts a bunch of holes in to shoot and excavate" Mother nature says " never mind, I got you bro "

Always thought of these open pits as solid rock excavations . I would have never expected this kind of slope failure. I remember many years ago going the bottom of the pit at Utah Mines /Island Copper ,i believe they were almost 1400 feet below sea level,with the waters of Rupert Arm lapping at one side of the mine. If id seen this i would have never gone down there.

I've spent a fair amount of time in shovel pits. There was a rule that you had to be a certain distance from the working face. I want to say it was 2x the face but I can't remember. Haven't been in a mine in about 5 years.

To quote my comment on the other linked thread about the Kennecott pit wall failure...... "I would point out that sloughs are part and parcel of open pit mines. I've been personally involved in one in Africa, seen the photos of Freeport in Indonesia, and now seen the photos of this one. All of them involved the movement of major league amounts of material (10+ million tonnes minimum). It's part and parcel of open pit mining. As one mine planning engineer once told me, the perfect mine plan for an open pit is after however many years of mine life that it has, the pit walls collapse just as the last truckload of ore leaves the pit. It's going back to the "funnel" I mentioned before, as you go deeper more waste has to be removed so you steepen up the walls of the pit as much as possible in order to reduce the amount of waste that has to be moved and so keep total costs down. The result of this is (to paraphrase Kevin Costner) - "Some days you win, some days you lose, some days it rains" .............