Originally Posted by minemechaz

Good day, we have been having a problem with our shovels and their teeth:

When loose, a tooth comes off the shovel and mixes with the ore that goes into the haul truck. Afterwards, the haul truck takes the ore into the primary crusher (with the shovel's tooth somewhere inside). Then, when the ore is dumped into the primary crusher, the tooth gets usually trapped between the liners and the mantle, resulting in an important downtime repair because of having to remove the tooth from where it is located.

Our question is to know if there might be some way to develop a system that can hold the tooth in case it comes off the shovel. This way, the tooth could be recovered on time, before becoming an issue inside the crusher. I have not heard of attaching systems yet because of the possible wear problems, but I've heard of some sensors that can be installed on the tip of the shovel so when a tooth comes off, the sensor can send a signal to the cabin and shoot an alarm or something so the tooth can be recovered on time.

Any help will be greatly appreciated, thanks!

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Assuming you have Essco teeth and mounting fingers on your mining shovels-

adding normally closed switches as sensors is waste of money and they will not last and the wiring will be destroyed.

It will be come a matter of inspecting the teeth every couple of hours to check for loose teeth and mounting pins or biting the bullet an welding them in place period.

decide how much wear the teeth are receiving and then decide if welding them in place is the better way to solve the problem- up until repalcement teeth came into use the teeth were welded to the buckets anyway!!

I would contact the folks who make the bucket teeth and they will probably tell you what I have told you already.

lzaharis ■

Dear Mr. Sergio Mendoza,

I think the company „THERA SENSORICA“ (Rudolf Salinger Platz 1/4/412, 1030 Wien, Tel.:0043 676 320 936 5, 0043 17157267909) could help you.

Regards

Michael Prenner

DI Dr.mont. Michael Prenner

Montanuniversität Leoben

Lehrstuhl für Fördertechnik und Konstruktionslehre

Franz-Josef-Straße 18

A-8700 Leoben

Tel.: 0043 3842/402-2803

Fax: 0043 3842/402-2802

Email: Michael.Prenner@mu-leoben.at * ■

We've been working on a prototype for remote sensing of this issue. It incorporates RFID but has some limitations as described in earlier posts, mainly durability and signal penetration. We are interested in further development of the concept with operations partners in conjunction with the RFID specialists and wear parts suppliers we have already been dealing with. Please contact through our website.

As an alternative, a VGF with grizzly bars set to allow the tooth sizing to pass as undersized in front of the primary, with a suspended magnet over the discharge belt, is a quick fix but affects to the downstream process design have to be addressed.

Matt Madsen

www.crushersinternational.com ■

The problem of teeth and occasionally adaptors becoming lodged in the crusher is not an uncommon problem and can cause significant risks in the removal.

The solutions I have found are:

1. Use good ground engaging equipment with regular inspection the teeth (at least twice a shift), by the shovel operator and maintenance.
   
   
2. Manage the bucket lips by tracking life and inspections so cracking and loss of the whole tooth is managed.
   
   
3. Use teeth smaller than the crusher and put a tramp metal magnet downstream of the primary crusher.

The use of sensors in such a harsh environment (in the teeth) would be a technical challenge, there are some image recognition technologies (spot the lost tooth) which could be used but the dust levels in the vicinity of the shovel will limit their effectiveness. ■

Mr. Mendoza:

I am relaying a message that comes from Greg Bierie, Martin Engineering. Greg states that "I have never heard of a cable attached bucket tooth or anything similar but if it is a big enough problem they could dump the raw ore into a hopper and feed the primary crusher with a conveyor with suspended magnet(s) to catch teeth, bolts, tramp iron. etc."

If you decide to go the hopper/belt feeder magnet direction, Mr. Bierie can be contacted at gregb@martin-mesg.com for additional information or another contact is Applied Conveyor Technology (sales@groupact.com) based in Fontana, California.

Thank you.

chuck fleming

chuckf@martin-eng.com ■

We had exactly the same problem on the South African gold mines and resolved it by cutting the bucket base back by about one foot and then welding in a replacement lip which had integral teeth. We found a number of local suppliers who came to the party with various designs for the thread insert helicoil ■

Angus,

I heard you left Rio. Where are you hanging out today? ■

I thought shovel teeth were basically manganese. Magnets would not be effective. Need a metal detector (after the incident) that could detect the piece on a non-ferrous feeder before the crusher or pattern recognition of the bucket lip profile, during each digging cycle.

Personally, I think pattern recognition would seem to hold the best promise, when considering all conditions. Maybe dithering laser, or ultrasonic, or other optical. These would require the operator to place the bucket in a position prior to the truck receiving clearance to continue from shovel to crusher. I would also believe this could be retrofited to the shovel in a novel way. I am sure we could do it. ■

I had seen this problem and was researching a solution with RFID tags. There were numerous challenges and I couldn''t find a manufacturer who produces the type of RFID Tag I was looking for. My objective in research is to get alert when the teeth is missing, and locate the teeth in the dump, using RFID tags. But, my research still continues.....

There is an alternative solution, like motionmetrics. A video camera monitors the teeth, with a pattern recognition software, when the teeth is missing, it will sound an alert that something wrong with the teeth. Another problem starts now, as which lorry was the teeth is in, it's really hard to find.

I have noticed that the teeth become yellow and sometimes red, because of heat. This heat causes the teeth to break. In this kind of temperatures, no electronics can work.. or may be they are under research. If somebody knows such RFID tags exists to withstand the red-hot metal, I would be interested to work with them to arrive a solution for this problem.

SHEIK ABDULLA J

Greeneco Consulting ■

Originally Posted by Richard Strachan

I am sure that any kind of "tooth missing" sensor will never be robust enough to survive in your operating environment. We had exactly the same problem on the South African gold mines and resolved it by cutting the bucket base back by about one foot and then welding in a replacement lip which had integral teeth. We found a number of local suppliers who came to the party with various designs for the lip but cannot recall the details of the final materials - I do recall though that the final solution used teeth that were cut into the insert material and not welded

Hope this helps,

Regards,

Richard.

Couldn't resist bringing Harry Belafonte to the party. Who was the female singer though?

This solution would to be the best in terms of pure simplicity, resilience, traceability & peace of mind. Baie Dankie, Richard. ■

Hi there,

Searching the web to see what's new in tooth breakage inquiries, I came across this interesting chain of posts. Please visit our company website at www.MotionMetrics.com. We are based in Vancouver, Canada, and have a flagship product (ToothMetrics) which we have now installed on various types of shovels (P&H, Bucyrus, Terex, and Liebherr) in various mines around the world. It is a field proven, machine vision (camera system + embedded PC-based computing platform) based solution which can be expanded with area surveillance (ViewMetrics), fragmenation analysis (FragMetrics), and most recently radar based proxmity sensing (RadarMetrics). We have a large install base of ToothMetrics. Our systems have successfully detected missing teeth in many of the mines. Please contact us directly at sales@motionmetrics.com and we can provide you with a list of our customer contacts for reference.

In response to a few of the messages, let me explain a few items:

1) As correctly mentioned in several posts, the mining environment is very harsh. As such, we chose our hardware platform after many trials back in 2001-2005. Our current hardware is custom-made and very suitable for various types of mining shovels and lasts reasonably a long time. Too many details to list here. Please contact us for further information or check out the information in our webpage.

2) All of our products come with a powerful logging feature. Essentially, the system keeps record of the images (compressed JPEG format) and numeric detection results for months. The shovel operator can easily browse the previous (history) images which are time stamped to get a good clue when the tooth came off and get an idea where it may be. In one mine in Chile, our system detected 3 consequtive tooth breakages in a matter of 3 hours. This was roughly 18 months ago.

3) We do not claim that our system addresses the tooth breakage problem 100%, however, we have a very good solution to the problem that works in majority of cases. We have received many repeat orders. We currently have customers in Canada, US, Chile, Peru, Australia, Indonesia for open pit mines that dig copper, gold, iron, diamond, silver, and most recently oil sands. We have worked on our solution for the past 10 years. Our software (with embedded image processing algorithms) is quite advanced and we have kept improving it with feedback from our customers.

Best regards,

Shahram Tafazoli

Motion Metrics Int'l Corp ■