MANAGEMENT IN ACTION – TYRES An airlift of Eurotire to resolve a critical supply shortage using an Antonov An 124 transport aircraft Treading carefully T HERE has been a

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MANAGEMENT IN ACTION – TYRES An airlift of Eurotire to resolve a critical supply shortage using an Antonov An 124 transport aircraft Treading carefully T HERE has been a Powered By Docstoc

An airlift of Eurotire
to resolve a critical
supply shortage using
an Antonov An-124
transport aircraft

Treading carefully
            HERE has been a marked shortage of tyres
            in the mining world since 2004, mainly
                                                            To coincide with the forthcoming Mining for Tyres event in
            because of a lack of foresight (from both
            suppliers and users) and a corresponding
                                                            Perth, Paul Moore reports that the shortage in mining tyre
            lack of investment in time consuming            supply will get a lot worse before it gets better, but some
capacity expansion to avoid a lengthy supply/
demand imbalance. The new capacity that is planned          believe that valuable practical lessons in maximising tyre
will not have any major effect until 2008/2009 and
many feel that the supply crisis will not abate until at    life are being learned as a result
least 2012.
   Prashant Prabhu, president of Michelin                   get their own allocations from the manufacturers.        a customer and competition point of view this will
Earthmover Worldwide told Mining Magazine: “The             There are also a large number of brokers offering         likely by welcomed.
situation is not a crisis, rather it is a situation where   mining tyres on the spot market.                             However, for larger radials especially, the majors
there is a complete imbalance between supply                   From a supply point of view, the new eastern          still feel that any new entrants have an uphill struggle
and demand. Demand has increased much faster                European and Chinese suppliers that have entered         as the larger the tyre, the more investment both in
than anyone predicted – including customers”.               the international market for mining tyres are unlikely   monetary and technical terms, is required. “Because
The demand is also increasing faster than the tyre          to go away once the supply/demand improves – for         of the market imbalance, people want to participate
industry is able to put new capacity in place. It is                                                                 in the mining tyre business. We believe, however,
arguably easier to increase capacity for new trucks on                                                               that the technological hurdles and learning curve
an assembly line as opposed to installing capacity for                                                               for these new entrants remain high”, said Prabhu.
new mining truck tyres.                                                                                              In the ultra-class (63 in rim) tyre size, Michelin
   However, the situation is much more complex                                                                       and Bridgestone are likely to remain the only
than that – the market is divided into those with                                                                    manufacturers for the foreseeable future.
large allocations and/or long term contracts who
tend to deal direct with the manufactures– this                                                                      WHO IS TO BLAME?
includes most of the major mining companies, the                                                                     When tyres were plentiful, competition between
largest contractors and large OEMs; and the rest                                                                     the manufacturers for large mining and OEM tyre
of the market, including small contractors, small                                                                    contracts was fierce, therefore achieved prices were
to medium sized mining companies and single                                                                          not as high as the tyre companies would have liked,
operations and specialist OEMs, most of which tend          Many underground tyres, such as on this LHD, are         so there may have been a reluctance at the time to
to purchase tyres from regional dealers, which in turn      smooth without tread patterns                            commit to major capacity expansion programmes.

20 Mining Magazine December 2006
It is also important to remember that mining tyres
still represent a small proportion of overall revenue
for these companies compared to passenger or truck
tyres. At the same time, the tyre companies would
argue that the mining industry’s insistence on low
prices made investment in this sector more difficult
to justify.
    The mining business is worldwide so the majors
cannot afford to concentrate on one particular
region, but as in any other market, the big users
have a clear advantage in sourcing. Mr Prabhu told
Mining Magazine that Michelin has tended to favour
long term contracts with its customers, which also
helps in planning future capacity investments.
    The same is true of its main competitor. Bridge-
stone’s Shawn Rasey, executive director of North
American sales for off road tyres commented, “we
elected from the very beginning to align our avail-
able supply with existing key customers with whom
we have enjoyed a long standing loyal relationship.
In these instances, much of that was by contract
agreements that have been in place”.

The shortage has definitely, however, changed
the way the industry looks at tyres and made the
aftermarket a much more crucially viewed part of            Eurotire 40.00-57 bias tyres mounted on a Caterpillar 793D mining truck
sales. Tony Cutler, technical manager at leading
Australia-based mining tyre consultancy, Otraco             to the customer after the tyre is delivered, with          tyre manufacture – Vitoria in Spain and Lexington
International told Mining Magazine: “For most mining        engineers visiting sites to help customers achieve         in South Carolina. In December 2005, the company
companies, the tyre shortage has changed their view         their full value. However, we are now clearly finding       announced an US$85 million investment to increase
of earthmover tyres – they are no longer seen as just       that customers are more receptive to this information capacity at the Lexington facility by 2010, though Mr
a consumable, but as a strategy commodity. When             in terms of taking on board this advice and making         Prabhu commented that some of the new capacity
the supply-demand situation resolves itself over the        the tyre last as long as it should”. Mr Rasey echoed       will begin to come on-stream in 2007. Bridgestone
next few years, that perspective will probably revert       this: “Many major mines have made significant strides too is expanding at its huge Shimonoseki plant in
to the traditional view. Notwithstanding this, we, as       to improve operating conditions and adopt key tyre         Japan (increasing capacity by 20%), but this will not
an industry, need to lock in what we have learned           maintenance practices that are helping us to bridge        be felt until probably late 2008. So many feel that if
during this period so that it is not forgotten”.            the supply gap at some locations – simply by making        anything, the supply situation in 2007 will be worse
   Shimon Laber, the US-based Eurotire business             tires last longer.”                                        than 2005/2006. The most important distinction to
development manager commented: “Every major                                                                            be made is between the two main tyre design types
mining group is seriously redefining their supply            SUPPLIER SUMMARY                                           – radial and bias ply.
strategy. They recognise the criticality of tyre supply     Michelin, Bridgestone and Goodyear are often                  The big three (and Yokohama) are all focused on
and are devoting new resources to ensure steady             referred to as “the big three” in mining tyre supply,      higher-performance (and price) radials in the mining
supply. They are aggressively seeking new suppliers         followed by Yokohama, Toyo, General, Belshina,             market – Michelin solely so, though Bridgestone,
and devoting more time to tyre management”. For             Eurotire, Kumho and many Chinese brands. Then              Yokohama and Goodyear still produce bias mining
the large miners, this includes high level committees       there are some underground specialists – Nokian            tyres.
looking specifically at the problem of tyre supply and Tyres in Finland for example. India also has a number               Belshina, based in Bobruisk, Belarus and Eurotire
maintenance.                                                of manufacturers, mainly producing smaller sizes for       in Dnepropetrovsk, Ukraine are both well established
   Some would go as far as to say there was igno-           graders and small loaders or dozers.                       suppliers of large bias and smaller bias and radial
rance about tyres in the mining industry prior to the           Michelin has two main global locations for mining      tyres in the FSU countries and eastern Europe, such
shortage, simply because there was a plentiful                                                                                as Belshina’s key market supplying domestic
supply and users didn’t have to worry.                                                                                        truck maker Belaz. They have now entered the
   Tim Good, Goodyear off the road global                                                                                      export market in a big way and have built up
customer account manager commented:                                                                                           a good reputation among new customers in
“Customers are taking our advice to heart.                                                                                    North America and elsewhere – their products
They realise that tyre care – such as weekly tyre                                                                             are now seen as on a par with homegrown bias
inflation checks, regular tyre rotation, reduced                                                                               brands. Both produce bias tyres up to 40.00-57
payloads and driving slower – greatly improves                                                                                size which have proved competitive in key
tyre service life.”                                                                                                           markets.
   Michelin believes that there is finally a rec-                                                                                  Brad Harris, president of Agora Tire, a
ognition of the added value of tyres in mining                                                                                leading US-based mining tyre supplier with
and that the current prices better reflect the                                                                                 offices in Canada and New Zealand, told
technology involved in producing them. The                                                                                    Mining Magazine: “These names have become
market situation has also had an effect on the                                                                                 almost like boutique brands in the US mining
relationship with customers. Mr Prabhu com-                                                                                   market. They are of higher quality than most
mented, “Michelin has always been a partner            A Michelin tyre service truck dwarfed by a coal-mine haul truck                                    Continued on page 22

                                                                                                                                     December 2006 Mining Magazine 21

Continued from page 21                                                                                                                                                     produced radials up to 25 in rims and most
of the Chinese brands and are considered on a                                                   Chains are sometimes used on haul trucks to provide                        recently, some 27.00R49 radial tyres.
par with bias ply tyres from Bridgestone, General                                                             grip – in this case, at Codeclo’s Andina                        Much of the industry in China – both
and Yokohama”. Users have reported getting                                                                                                                                 manufacturers and exporters – is based close
similar hours of usage from these products. Both                                                                                                                           to Qingdao in Shandong province, which one
do also produce smaller radials – for example the                                                                                                                          source referred to as the “Akron of China”, a refer-
Belshina 18.00R25 or Eurotire 29.5R25.                                                                                                                                     ence to the importance of Akron, Ohio to the US
   In the current market, a lot more companies                                                                                                                             rubber tyre industry. Some of the better known
have looked again at using bias tyres. While                                                                                                                               factories in China include Shandong Linglong,
no-one would argue with the fact that radial                                                                                                                               Guizhou Tyre, Tutric and Qingdao Qizhou Rubber.
technology is superior in quality and durability to                                                                                                                        What can be confusing for customers is that
bias, market conditions have forced operators to                                                                                                                           some individual factories produce more than one
re-evaluate tyre deployment and optimise opera-                                                                                                                            brand so it is hard to pin down the exact origin.
tions by blending bias and radials. Shimon Laber
told Mining Magazine: “I think that equipment                                                                                                                              ASTRONOMIC SPOT MARKET
operators are rediscovering bias tyres. Many cus-                                    cases, even the bias ply tyres are not yet of a similar                                The other option – the spot market for mining
tomers have calculated that our bias tyre in certain                                 standard to established sources in Europe and North                               tyres has reached astronomical pricing for the largest
environments can be more economic than a radial                                      America. One source stated that due to a shortage of                              and most sought after sizes as the tyres are just not
tyre.” On the market evolution, Mr Laber added: “Our                                 57 in bladders in China, some 57 in rim tyres were be-                            out there. Spot prices for a 57 in rim radial tyre have
business has changed significantly in the past few                                    ing supplied with modified smaller bladders, which                                 been as high as US$150,000-200,000 – ten times
years. Higher tyre prices have allowed us to invest in                               can lead to overstretching and early fatigue in use.                              what they were only a few years ago. For an even
the production of higher quality bias tyres. We are                                  But while quality varies, there is no doubt that many                             more scarce 63 in tyre, prices have actually been
now using premium raw materials and investing in                                     of the Chinese products are getting a lot better. There                           bought for as much as US$300,000 and offered for
new technology.”                                                                     are several large and well known manufacturers mak-                               sale at even higher prices. Those companies that
   The Chinese only started making large tyres                                       ing real progress in quality with successful smaller                              have paid high prices tend to have been from the
suitable for mining several years ago and in many                                    radial products for wheel loaders. The Chinese have                               gold or copper sector as opposed to coal simply
                                                                                                                                                                       because of the cost of downtime at some of these
 THE OPTIMUM TYRE BY APPLICATION                                                                                                                                       mines can justify huge tyre prices to get a truck back
 According to leading mining tyre consultancy, Otraco International, there are seven main elements in                                                                  up and running.
 determining the optimum tyre specification for a particular application (eg tyre fitment to a particular haul                                                               It is also the case that the larger the tyre, the less
 truck on a particular minesite). These elements, generally in order of priority, if selecting from the big three                                                      manufacturers there are. Bias ply tyres are much
 manufacturers, are as follows:                                                                                                                                        more common than radials, as again, much fewer
 1 Construction: radial ply or bias ply – normally radial ply will provide in the order of a 30-40% higher tyre                                                        companies supply large radials due to the investment
   life than bias ply, eg. a 40.00R57 versus a 40.00-57                                                                                                                in technology required. Agora’s Harris commented:
 2 Size: fit the largest tyre size possible, eg. a 40.00R57 will provide in the order of 30-40% higher life than a                                                      “Comparing radial tyre manufacture to bias ply
   37.00R57 (standard size) on a 190 t haultruck                                                                                                                       manufacture is like comparing a commercial jet to a
 3 Tread depth: haul truck tyres can typically be purchased in standard depth E3 or deep tread E4 (150%                                                                propeller plane.”
   extra tread depth offering 30-40% higher tyre life). In recent years an E4+ has been incorporated by each                                                                Such is the demand that many of the brokers
   of the big three with an additional 10% depth over the E4. (Note that while an E3 is classified as “standard”                                                        offering tyres through email shots and other media
   depth, the vast majority of haultrucks worldwide are operated on E4 rather than E3 tyres).                                                                          do not actually have the tyres in stock, instead they
 4 Tread compound: available in a range of 3 to 7 steps, depending on the manufacturer, from ‘cut resistant’                                                           are part of a chain.
   through ‘standard’ and ‘heat resistant’; a super cut resistant compound may provide double the life of a                                                                The problem with a lack of knowledge about the
   super heat resistant compound – because it has better wear/abrasion resistance and better resistance to                                                             origin is not so much of a problem with new tyres,
   tread cutting.                                                                                                                                                      but for tyres that have been repaired, the customer
 5 Tread pattern: generally available in three main categories for haul truck tyres – rock lug, traction and rib                                                       may not know anything about the original damage,
   (still not very common, and not offered by many manufacturers). A rock lug pattern may provide 10-15%                                                                context of use and type of repair for the tyre meaning
   or more tyre life than a traction pattern tyre on a hard rock minesite. However, where road surfaces are                                                            it may not give the life expected, and in some cases
   clayey or muddy, a traction pattern may provide higher tyre life if its tread voids/grooves are able to                                                             may be dangerous to use.
   expel mud and slosh in the tyre footprint, thereby improving the tyre tread contact with the underlying                                                                 In some cases, mining operations have been
   competent road surface – reducing tyre slip relative to the road surface. A rib pattern is the best design of                                                       known to get their radial mining tyre allocation from
   the three for haulroads with bituminised (or other even and hard wearing) surfaces.                                                                                 the large manufacturer, then order bias replacements
 6 Brand: Michelin, Bridgestone or Goodyear – in any particular tyre size one brand may (and usually does)                                                             from another source like Belshina and sell the more
   offer a distinct advantage (perhaps in the order of 5-10%; sometimes considerably more) in life and/or                                                               valuable radials to dealers. This is frustrating for the
   operating cost per hour or kilometre over the other two.                                                                                                            large radial makers who do not want to see their new
 7 Star or Ply rating: generally radial ply haul truck tyres are of 2 star rating; however for bias ply tyres                                                          products on the open market.
   there is often a range of ply ratings – the greater the ply rating the greater the load rating of the tyre, and
   potential tyre life (perhaps up to 5% or higher).                                                                                                                   RADIAL AND BIAS EXPLAINED
                                                                                                                                                                       In a radial tyre, the sidewall and tread function
 ■ Elements 3 to 5 (particularly element 4) usually involve a trade-off depending on the TKPH (workload) rating of the tyre specification relative to the
   operational TKPH of the mining application. For example, if a standard (medium TKPH rated) compound is the optimum for the particular operation, then it            independently to deliver a large ‘footprint’ meaning
   may provide 20% higher life than a heat-resistant (high TKPH rated) compound; however, if using a cut-resistant (low TKPH rated) compound, the tyres may            the tread wears more evenly and slowly. The casing
   suffer an unacceptable level of low-life heat failures at an average life of half that of the heat-resistant compound.
                                                                                                                                                                       is made from a single ply of steel cords that do not
 ■ Similarly, a deep-tread E4 tyre may not be available with sufficient TKPH rating (even if it incorporates a heat-resistant tread compound) to handle the              scrub or rub allowing for cooler running. The crown
   particular mining application; in this case, one may need to select a standard-depth E3 tyre. The same applies in relation to tread pattern – a rib pattern
   generally has higher TKPH rating (other things being equal) than a traction pattern; and the traction pattern a higher TKPH rating than a rock lug pattern.
                                                                                                                                                                       is stabilised by steel belts for improved resistance
                                                                                                                                                                       to punctures and tears. In a bias ply tyre, the casing
 ■ On the other hand, tyre selection based on the rules-of-thumb noted above for elements 1, 2, 6 & 7 will almost result in higher life (marginal though it may        is made up of diagonally criss-crossed fabric plies,
   be in the case of ply rating) irrespective of the application. Radial tyres have a higher TKPH rating than bias ply tyres, and larger-sized tyres have a higher
   TKPH rating than smaller-sized tyres.                                                                                                Source: Otraco International   stacked one of top of the other and wrapped around
                                                                                                                                                                                                           Continued on page 24

22 Mining Magazine December 2006
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Continued from page 22                                                                                                 REPAIRS AND RETREADS
the bead wires which anchor the tyre to the rim                                                                        Retreading refers to the process of replacing the
to form the casing or air chamber. The crown and                                                                       tread layer on a tyre. The tyre is buffed back to its cas-
sidewall are formed from the same structure. The                                                                       ing, repaired and rebuilt using fresh tread compound.
only way to increase the strength of bias tyres is to                                                                  Retreading, in times of adequate tyre supply, is a high
increase the number of plies and bead wires. More                                                                      cost option for managing large mining tyres – as
plies means more mass, increasing heat retention                                                                       tyres become larger they work relatively harder and
and reducing tyre life. As the bias tyre casing is                                                                     there is less margin for weakening of a tyre’s structure
constructed to form one working unit, when the side-                                                                   that occurs during autoclave curing of the retread.
walls deflect, the tread squeezes in and distorts. This                                                                 There are many other management options that can
makes the tire scrub or squirm, decreasing traction,                                                                   be more cost effective. But the retread market is set
operator control and accelerating tread wear.               A Sandvik coal hauler with Infinity brand tyres from        to remain buoyant for some time.
                                                            Al Dobowi                                                      Several mining companies are actively looking
TYRE RIMS                                                                                                              into projects to set up retread facilities of their own.
The tyre rim is the metal assembly that connects the        and super-elevation of corners. It can also highlight      It is probably the case that this kind of development
tyre to the vehicle, consisting of a base and either a      mine operator practices such as cornering speed and        would be most successful in single highly concen-
side ring or a side and lock ring combination, which        truck turning profiles at dumps. The most common            trated mining areas (eg. Alberta oil sands, Nevada
are removable from one side for tire mounting. The          measure applied to mining tyre studies is the tonne        gold, Minnesota iron ore).
opposite side has a fixed flange to retain the tire. One      kilometre per hour or TKPH, a Implementing real-               It is also true that the major manufacturers are
of the leading players in this area is Canada’s Rimex,      time TKPH (tonne kilometre per hour – a system of          very much involved in retreading of truck tyres so it
which specialises in developing advanced wheel              rating tyre workload capacity) monitoring and truck        would just take one of them to make the decision to
technology to precisely match modern mining radial          scheduling to maximise tyre working efficiency               take the market on that route. Most of those sources
tyre designs. According to Rimex, the introduction             Trial projects can be implemented to improve            contacted thought this unlikely for the time being.
of the radial tyre has had “an important and serious        mine haul roads and dump conditions, such as using         But the attitude of the majors to tyre repair is mixed.
impact on rim performance”. Due to the special              an impact roller on dumps or using haulroad addi-          On the one hand there is recognition that in the
construction of the radial tyre, it has a more flexible      tives. For multiple site mining companies, matching        current supply/demand situation it is an important
sidewall, causing more movement in the bead area.           equipment fleets to operations to optimise tyre             part of the market and there has been a definite
    The two major Rimex products for the mining             performance by minesite application.                       major upswing in the retreading business. However,
market are the Taper Secure Radial (TSR) Series of                                                                     retreading (of large mining tyres particularly) is a
rims and wheels.The tapered design secures all rim           GLOBAL MINING TYRE                                        specialist business and some argue that it is difficult
components in place. It also eliminates any move-            PRODUCTION – THE MAJORS                                   to assess the value of a retread, when you compare
ment or flexing of the rim components (side rings,            Manufacturer Mining tyre     Expansion                    the cost of removing the tyre, transporting it to and
rim base, bead seat band, lock ring, and o-ring). The                     production      plans                        from the retread facility and refitting it versus letting
beads of the tire are secure and stable. Air loss and                     locations                                    a new tyre finish its life. The major manufacturers
the problems associated with it are eliminated.                           (excludes some                               also argue that there is the issue of the retreader not
    According to Rimex, in a typical 57 in rim                            small capaci-                                knowing the exact nature of the operating conditions
assembly, there is only 138 in2 of contact between                        ties elsewhere)                              that the tyre was subjected to before removal from
the flange and back section. At 120-psi tire inflation                                                                   service. Chris Skelton, managing director of UK-based
pressure this works out to 7600-psi pressure. A 57 in        Michelin          Vitoria, Spain;     50% capacity        earthmover tyre repair and retread specialist, OTR
TSR rim assembly at 120 psi inflation pressure has                              Lexington,          expansion at        Tyres Ltd, told Mining Magazine: “Retreading is an
2.5 times more contact area between the flange and                              South Carolina      Lexington by        option for mining companies but it has to be done
the back section. As a result, the contact pressure is                         Campo Grande,       2010; some          properly. There are retreads and there are retreads.”
reduced to only 1,350 psi.                                                     Brazil (from        extra capacity          The retread/remould and repair market has also
    The Machined Extreme Service (MES) series of rims                          2007); Water-       online by end-      evolved – at the beginning of the shortage situation
is the Rimex answer to the more aggressive radial                              ville, Canada;      2007                a number of companies tried to enter the market for
tyres used in open pit mining applications. The three                          Zalau, Romania;                         repairing or retreading large mining tyres but only
areas of benefit to the customer are extended rim                               Le Puy and                              those that have developed the technology required
life, increased safety levels and extended tyre life. The                      Montceau,                               have really succeeded, while many mining companies
MES manufacturing process using special machining                              France                                  that sampled below standard retreads or remoulded
can increase the steel mass of the rim by up to 100%                                                                   tyres in the early days of the shortage and found they
in critical areas. Each component is fully machined          Bridgestone       Hofu, Japan;        20% capac-          barely lasted for any extra usage at all. The retreaders
from rolled steel to ensure optimal roundness. This                            Shimonoseki,        ity expansion       that have been successful are the ones whose tyres
means better component fit and better tyre fit on the                            Japan;              underway at         have proven themselves in use many times. Larger
rim base. This translates into longer component life                           Bloomington,        Shimonoseki         and respected retreaders and remoulders include OTR
and longer tyre life.                                                          Illinois;           probably            Tyres, Bailac Group in South America and in the US
                                                                               Des Moines,         on-stream late      market, J&M Tire and RDH Tire & Retread.
LEARNING FROM EXPERIENCE                                                       Iowa                2008
So what are mines doing to maximise tyre life? This                                                                    UNDERSTANDING TYRE SIZES
is where the experience of companies like Otraco             Goodyear          Topeka, Kansas;     No new capac-       In the nomenclature, such as in 55/80R63, the 63 at
comes in. Options include converting equipment to                              Colmar-Berg,        ity planned.        the end refers to the diameter of the rim of the tyre
larger than standard tyres (typically increasing tyre                          Luxembourg;         Strike action af-   in inches, the letter R refers to radial and the initial 55
life by 40% and reducing tyre purchase requirements                            Tatsuno, Japan      fected produc-      is the section width of the tyre (width of a new tyre,
by 30%).                                                                       (Nippon Giant);     tion at Topeka      including 24- hour inflation growth and including
    Companies can also conduct VBOX studies – VBOX                             Americana and       plant in 2006       normal sidewalls). In other tyre sizes only the width,
is a GPS-based monitoring system that can help to                              Sao Paulo, Brazil   but continued       type and rim diameter are given eg. 40.00R57 and
identify and rectify problem areas in mine road de-                                                to operate          sometimes the section width is instead given in mm
sign, particularly road gradient level and consistency                                                                                                     Continued on page 26

24 Mining Magazine December 2006
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                    Products and Equipment

Continued from page 24                                       (including traction pattern) tyres. The downside of a        TYRE CHECK LIST – LARGER RIGID
instead of inches. In bias ply tyres, the R is replaced      smooth tread tyre, particularly in haul truck applica-       DUMP TRUCKS
by a dash, eg. 40.00-57.                                     tions, is that it has poor heat dissipation which results   Truck (nominal              Manufacturer          Radial
   The 80 in 55/80 is a percentage measure of the            in a TKPH rating that would be too low for most             payload – t)                                    tyre size
tyre’s profile, ie. the depth of the sidewall (the wall at    surface mining operations.
the side of the tyre). The profile is expressed as a %           Dubai-based tyre company Al Dobowi Group is              789C (177)                     Caterpillar    37.00R57 or
of the tyre’s section width. For example the 55/80R63        a relatively new entrant to the mining tyre market,                                                         42/90R57
tyre has a profile or sidewall that is 80% of the 55 in       but is a long standing supplier of passenger vehicle        793D (218)                     Caterpillar    40.00R57 or
section width. The benefit of low profile tyres is that        and commercial truck tyres. Al Dobowi executive                                                             46/90R57
they give greater control and better handling when           director Harjeev Kandhari told Mining Magazine that         797B (345)                     Caterpillar      59/80R63
cornering.                                                   less than two years ago it made a strategic decision        730E (186)                      Komatsu       37.00R57 or
                                                             to focus on underground mining, which as a market                                                           42/90R57
                                                                                                                         830E (231)                         Komatsu    40.00R57 or
UNDERGROUND TYRES                                            suffered from suppliers offering standard off the road
All the majors have underground tyre ranges. How-            products when the underground conditions required           930E (290)                         Komatsu      53/80R63
ever, the market also includes some specialist sup-          a specific design focus. For example, a major problem        EH3500 (171)                        Hitachi   37.00R57 or
pliers, such as Nokian Tyres in Finland (Mine L-5S and       in underground loaders is damage to the sidewall                                                          42/90R57 or
Mine L-5S TL), which is a major supplier to Sandvik,         area of the tyre due to excess loading.                                                                      36.00R51
Atlas Copco and other underground machine OEMs.                 This has been combated using special compound-           EH4500-2 (254)                      Hitachi     50/90R57
Martti Päivinen, R&D manager at Nokian Heavy Tyres,          ing techniques to make a much more heavy-duty               EH5000 (286)                        Hitachi     53/80R63
told Mining Magazine: “The machines used differ               tyre to withstand added stresses. The company said          T252 (183)                         Liebherr   37.00R57 or
when comparing the underground and surface mines.            that its engineers had spent a lot of time at under-                                                      40.00R57 or
Often shorter distances are driven in underground            ground mines looking at the causes of tyre fatigue
                                                                                                                         T262 (218)                         LIebherr   40.00R57 or
mines than surface mines. Underground mine tyres             and damage.                                                                                                 46/90R57
primarily need high wear and cut resistance proper-             The tyres are made under contract in China under         T282B (360)                     Liebherr        55/80R63
ties. Surface mines by contrast, such as dump truck          the Infinity brand at an operation north of Qingdao in       MT3700AC                     Terex Unit Rig   40.00R57 or
tyres, need to have high heat and wear resistance,           Shandong province. The moulds for the Infinity range                                                         46/90R57
though cut resistance properties are needed”.                were designed by Al Dobowi and it has employees in          MT4400 (218)                 Terex Unit Rig     46/90R57
    Underground tyres (usually loader/bogger tyres,          China to monitor the production process.                    MT4400AC (236)               Terex Unit Rig     46/90R57
but sometimes truck tyres) often incorporate a                  The company has already worked with Sandvik              MT5500 (326)                 Terex Unit Rig     55/80R63
smooth tread (slick) pattern – this offers the maxi-          on tyre delivery for its OEM coal haulage equipment         75306 (220)                      BELAZ           40.00R57
                                                                                                                         75600 (320)                      BELAZ          55/80R63
mum resistant to wear, cutting and penetration and           such as the Eimco ED loader ranges assembled at the
lug tearing (as there are no lugs to tear). Contrary to      Voest Alpine Mining and Tunnelling (VAMT) plant in            Source: Bridgestone OTR, Japan
common perception, a smooth tread pattern gener-             Tomago, near Sydney, Australia.
ally also provides superior traction to a lug pattern           Manufacturing of the loader’s steel structure is         more prone to damage. Different chain patterns are
                                                             performed by Dimitriou Fabrications, at their pur-          used depending on the application. For tougher
                                                             pose-built facilities in Sydney’s west, and Newcastle.      conditions eg. hard, abrasive rock or metallic slag
                                                             Previously manufactured offshore, EIMCO loaders are          tighter diagonal chain patterns are used and for
                                                             now only manufactured in Australia but are widely           other rocks eg. a soft limestone, a more open pattern
                                                             exported to markets such as Russia, China and South         is adequate. Chains are also used on mine trucks, but
                                                             Africa. VAMT competitor Joy has also used Infinity           mainly serve to provide grip, such as where trucks
                                                             tyres on some of its new equipment.                         are negotiating steep haul roads in icy conditions,
                                                                                                                         similar to using a snow chain. In wheel loaders, some
                                                             TYRE CHAINS                                                 companies swear by having chains on all four wheels,
                                                             There are two main manufacturers of chains                  while others will only use them on the front tyres
                                                             – Austria-based Pewag and Germany’s Rud Chains.             (which bear the brunt of the wear) and have slightly
                                                             The largest market by far for mining tyre chains is         larger tyres on the back to even up the two pairs. On
                                                             on wheel loaders, where the machines are operated           a loader, chains can extend the tyre life by as much
Wheel loaders represent by far the largest market for        on very uneven ground close to blasted rock or              as three times. The chains themselves are made from
mining tyre chains                                           stockpiles, and where as a result tyres are much            hardened chrome-nickel steel.

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26 Mining Magazine December 2006

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Description: Service Level Agreements Tyre Industry document sample