Insurability of Large Gearless Mill Drives (GMDs)
Introduction. We have written on risk associated with large ring motors in gearless mill drives previously [1, 2, 3]. In [1], we observed that ABB and Polysius were far too confident in 2001 when they claimed that 42 and 44 ft diameter mills and ring motors posed only manageable risks and that a 44 ft mill and GMD design was ready and waiting for a purchaser [4].
(PDF) Investigating the effective factors on chromium ...
Application of the proposed method in a 9.75×4.88m SAG mill indicated that the liner wear profile along the liner length is non-uniform and the highest …
Ring-geared mill drives - Grinding | ABB
Mill application features. Frozen charge protection – Detects frozen charge in the mill, minimizing equipment wear and liner replacements.; Coupling supervision – Detects if a failure or slippage occurs in the couplings and stops the system in case, preventing major damages.; Stand-still detection – Prevents the motors from re-starting if the mill is still rocking or moving after a stop ...
Troubleshooting roll defects - causes and corrective actions
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GOLD ROAD-GOLD FIELDS: NEW PLANT FAILURE CUTS GRUYERE ...
Mechanical issues are continuing to disrupt operations at the Gruyere gold mine, the 50-50 joint venture project of international miner Gold Fields and local Gold Road Resources in Western Australia's Yamarna greenstone belt 200km E of Laverton.Gold Road says the failure of a trunnion bearing forced the shutdown of the Gruyere ball mill on Sept 28, leaving the …
Using IR Windows to Monitor Commutators on Critical Motors ...
The SAG mill motors are so critical to Kennecott Utah Copper Mine's 24x7 processes and are extremely labor-intensive and expensive to change out in the event of failure. Installing IR windows to monitor the commutator and brush assembly during operation has allowed thermographers to safely and efficiently gather a critical data point that will ...
Tumbling Mill Working Capacity Influencing Factors
Tumbling mill is also known as a ball mill or rod mill. They are all composed of a cylindrical cylinder lying horizontally on the bearing, and the material is ground into powder by rotating the cylinder. When we want to discuss the factors that affect the tumbling mill working capacity, we must first know the working principle of the tumbling mill.
MECHANICAL PROPERTIES OF ENGINEERING MATERIALS
Mechanical engineers calculate those forces and material scientists how materials deform (elongate, compress, twist) or break as a function of applied load, time, temperature, and other conditions. Materials scientists learn about these mechanical properties by testing materials.
MTBF, MTTR, MTTF, MTTA: Understanding incident metrics
MTBF is a metric for failures in repairable systems. For failures that require system replacement, typically people use the term MTTF (mean time to failure). For example, think of a car engine. When calculating the time between unscheduled engine maintenance, you'd use MTBF—mean time between failures.
SAG Milling in Australia -Revised Submission
MW). It has been the industry standard for SAG mills above 13 MW capacity. However, pinion systems to 8 MW per pinion and dual motor systems with quadruple pinions extend the range of gear driven mills to a theoretical limit of 32 MW. The Ernest Henry SAG mill (11 MW) is currently the largest twin pinion single drive mill installed in Australia.
Report of Foreign Issuer Pursuant to Rule 13a-16 or 15d-16 ...
backfilling. The SAG and Ball mill foundations were completed and mechanical installation commenced. Structural steel installation at the grinding area continued progressing and the bridge crane was erected. The installation of three out of four leaching tanks and five out of nine CIP tanks commenced. All plant thickeners foundations were completed
(PDF) A mechanistic model of SAG mills
Figure 3 3D image of the pilot scale sag mill ... in a ball mill, where the mechanical environment was predicted using the Discrete Element Method and breakage of …
Wear and Failure Analysis of Semi-Autogenous Grinding …
12%The wear and failure analysis of shell liners of a grinding mill is investigated. Metallurgical and tribological studies were conducted on the worn liner of a semi-autogenous grinding mill in Chadormalu Industrial Complex. The chemical analysis, wear mechanism, microstructural variations and mechanical properties in different sections of the …
Accident at Juaben Oil Mills: 3 lives lost, incident was a ...
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OPERATION AND MAINTENANCE OF CRUSHER HOUSE …
The failures of these equipments have led to high maintenance and operation costs. The reason ... consist of a crusher followed by a SAG mill followed by a ball mill. In this context, the SAG ... force amplified by mechanical advantage through a material made of molecules that bond together more strongly, and resist ...
Gearless mill drives - ABB
• 28 MW GMD for a 40' SAG mill • 28 MW GMD for 42' SAG mill Whether it is size or an installation at the highest altitude (4600 m.a.s.l.), ABB's GMDs are well positioned to contribute to the building of larger and ever more powerful mills. — Leading the gearless mill drive evolution The ABB gearless mill drive (GMD) is the most powerful ...
Minding the Grind: Maintenance Options to Keep SAG Mills ...
Minding the Grind: Maintenance Options to Keep SAG Mills Turning. Purpose-built structures such as the Skyway system from Russell Mineral Equipment can provide a stable, safe and efficient platform for mill liner bolt removal when compared with the common approach of hanging jackhammers and impact wrenches from a chain hoist.
Ball Mills - Mineral Processing & Metallurgy
Ball Mills can be supplied with either ceramic or rubber linings for wet or dry grinding, for continuous or batch type operation, in sizes from 15″ x 21″ to 8′ x 12′. High density ceramic linings of uniform hardness male possible thinner linings and greater and more effective grinding volume.
The Selection and Design of Mill Liners - MillTraj
Mill linings, Rubber Engineering, Salt Lake City, UT 84126, United States of America . ABSTRACT . Dramatic shortcomings of mill liner designs, especially of large SAG mills, - such as rapid failure and even mill shell damage arising from impacting of the charge directly on the liner, and unsuitable
Literature Review: Gearless Motor Failures – A Mill ...
The Collahuasi motor was for a 40 ft SAG mill. The Antamina 38 ft SAG mill was also driven by an ABB motor and the hanger plates had not failed on that machine after several years of operation. Similarly, the Sossego motor for the 38 ft SAG mill had not failed. It too had an ABB motor and it had operated longer than the Collahuasi motor.
A Guide to Reliability Prediction Standards & Failure Rate ...
In many cases, 217Plus failure rate predictions are not as pessimistic as MIL-HDBK-217. China's GJB/z 299 is employed almost exclusively in China, or in companies doing business with Chinese companies. The failure rate estimates from China's GJB/z 299 tend to be very divergent from the other standards, especially for microelectronic devices.
The magic of bolting for a grinding mill assembly - ...
However, grinding mills play a critical role in minerals processing, with large mills often processing over $1 million worth of ore per day. With grinding equipment operating around the clock, any revenues lost due to a mechanical failure are lost forever and can severely impact a mine's bottom line. Every grinding mill part has a role
Elastomer Engineering Guide - James Walker
• Good mechanical properties • The ability to adhere to various fibres, metals and rigid plastics. Also, by proper selection of compounding ingredients, products with improved or specific properties can be designed to meet a wide variety of service conditions. This remarkable combination of properties is the reason elastomers serve a vast
What is Fatigue Testing? - WMT&R
What is Fatigue Testing? 1. From Latin "Fatigare" meaning "to tire." 2. Engineering terminology: - damage and failure of materials under cyclic loads. 3. Fatigue testing is defined as the process of progressive localized permanent structural change occurring in a material subjected to conditions that produce fluctuating stresses and strains at some point or points and that may …
Frozen charge detection and automatic loosening with ...
failure. The consequences of such an occurrence are inten- ... Chile equipped with one 40ft SAG Mill of 22 MW and two 26ft Ball Mills of 16.4 MW commissioned in 2011. In the ... the charge by mechanical means made the mill able to resume work after some hours.
SAG Mill Grinding Circuit Design - 911metallurgist
As a result, under-sizing an SAG mill has disastrous results on throughput— across the industry, there are numerous examples of the SAG …
ABB Library - Gearless Mill Drives
Paper held at SAG Conference 2011 - By S. Gaulocher (ABB), K.S. Stadler (ABB), Th. von Hoff (ABB), R. Veldsman (ABB), A. Fuerst (ABB) and J. Koponen (ABB): Gearless mill drives (GMDs) are the workhorse in the mineral processing industries, more specifically when it comes to grinding crushed ore and cement (in various production stages) in semiautogenous (SAG) …
Mechanics of Materials-Deflection
Beams deflect (or sag) under load. Even the strongest, most substantial beam imaginable will deflect under its own weight. Under normal conditions, the actual amount of deflection in floor beams is generally un-noticeable as shown in Figure 1.
Join Tega at 2019 SAG Conference - Tega Industries
"A Chilean Copper mine with 40 feet diameter SAG mill processing 4300 tph was facing very low avaliabilty due to continues unexpected shutdowns for failures on liners by cracks. Several kinds of alloys and designs were provided but results were out of …
ARE SAG MILLS LOSING MARKET CONFIDENCE?
AG or SAG mills have been in use in comminution circuits since the 1950's and are considered a mature technology in most countries. However, a reasonable number of recent SAG mill based projects ... Major mechanical failure, or Under estimation …
Steel Grinding Balls Failures in Drop Ball Test (DBT)?
If the balls' target environment is e.g SAG mill or large diameter balls mills, there are no two ways about it, you have to re-temper them to improve impact toughness which is much needed in the ...
c est quoi sag mill - stockbrot-baeckerei.de
[randpic] Mill Sag Mechanical Failure - greenrevolution. The ball mill as a means of investigating the mechanical failure of Conga: The world's first 42-foot diameter 28 MW gearless S mill. failures have not occurred in large GMD S mills, the mill design was not exempt from a reliability survey. . Read More
Material Test Report FAQ | MTR Frequently Asked Questions ...
Failure to accurately communicate a material's physical and chemical properties can lead to issues that may result in catastrophic failure or even loss of life. This is why MTRs are of critical importance during and after manufacturing processes. Other common names for Material test reports include: Certified Mill Test Report
Milling - Energy intensive and high maintenance
a technical paper on the occasion of the SAG 2006 in Vancouver, B. C. Canada: "Lessons learnt from recent failures of gear drives on mills in South Africa" This study came up with the conclusion that failures occur in five main areas of a mill drive train: • Gear reducers • WRIM rotors • Pinion bearing housings • Pinion shafts
Mines Safety Significant Incident Report No. 187
still in place inside the ball mill when the top liner plate was dislodged and fell, pinning him to the ground. A mechanical lifting device was required to lift the liner plate from the worker. He sustained extensive injuries, including compound leg fractures, fractured vertebra, and crush injuries to his chest. Probable causes Direct:
Coupling Alignment Fundamentals - Rexnord
Coupling Alignment Fundamentals Rexnord, 5555 S. Moorland Rd., New Berlin, WI 53151-7953 538-214 Telephone: 262-796-4060 Fax: 262-796-4064 February 2014 August 2013