In rock and stone processing, during the crushing process various short-term or prolonged overload situations can arise. The overload systems of the MC 110 EVO2 and MCO 90 EVO2 pursue an important goal: increase in the operational readiness of the plant in a sustainable manner by guaranteeing a crushing process that is as continuous as possible. Both crushing machines are equipped with mechanically and software-supported overload systems.
 Overload system on the jaw crusher MOBICAT MC 110(i) EVO2
With its multi-stage overload system, the jaw crusher MOBICAT MC 110(i) EVO2 provides more safety with uncrushable material. If, for example, metal enters the crushing process, the crushing gap (CSS) opens automatically in up to two seconds over the complete gap range. The crusher itself does not have to be stopped during the temporary overload situation, which means that the crushing chamber is empty and manual clearing of the crusher is not necessary which saves work and time. When the overload situation is corrected, the system then moves back to the original crushing gap and the crushing process is continued. The pressure plate installed as a predetermined breaking point is preserved. The consequences are reduced downtimes and increased crushing capacity.
Active overload system on the jaw crusher MOBICAT MC 110(i) EVO2 for reduced downtimes and increased crushing capacity. Photo: Wirtgen
Overload systems on the cone crusher MOBICONE MCO 90(i) EVO2
The cone crusher MOBICONE MCO 90(i) EVO2 has two different systems installed. The overload system “Tramp Release” protects the crusher against uncrushable material such as wood or metal. The bowl including the bowl liner lifts automatically to allow uncrushable material to fall through. The “Ringbounce Detection”, on the other hand, reacts to an excessively high share of fines in the feed material and prevents “briquetting” – which means the clogging of the crusher or sticking together of the material. Here, the hydraulic pressure of the crusher is monitored continuously. The system reacts as required and therefore prevents latent overloads. Depending on the machine application, the “Ringbounce Detection” can be oriented via the control system to output (“Mixture Mode”) or product quality (“Precise Mode”).
Intelligent “Ringbounce Detection” with the cone crusher MOBICONE MCO 90(i) EVO2 reacts to an excessively large share of fines in the feed material and prevents clogging of the crusher. Photo: Wirtgen
By preventing machine damage and thus production downtimes, the overload systems from Kleemann therefore guarantee increased operational reliability for the users.
The new MOBISCREEN MSS 802(i) EVO offers users a mobile, efficient screening plant that was designed to meet changing challengesin different application areas. With its well-thought-out plant design and flexible conversion options, Kleemann demonstrates how a high material flow can be guaranteed in natural stone and recycling applications.
Screening made easy
With the development of the MOBISCREEN MSS 802(i) EVO, a new generation of screening plants and successor of the MS 15 Z, Kleemann consciously places the focus on the user perspective. The technology behind the screening process must be easy and safe to use for all users. The new plant impresses not only with technological highlights in the process sequence, but also through its ergonomic design, optimised operation and the user-friendly maintenance concept.
Improved mobility and flexibility in application
With its proportionally controlled running gear, the plant can be quickly relocated either by a low-loader to the job site or within the building site. Apart from other improvements of the new MSS 802(i) EVO, folding of the side discharge conveyors without the need for disassembly clearly reduces set-up times. Increased application variability is provided by a hopper rear wall that can be folded to three heights, which permits feeding of crushing plants with a lower discharge height. The large offer of screen surfaces and simple adjustment of the screen parameters, which make rapid adaptation of the MSS 802(i) EVO to a very wide range of feed materials possible, reduce set-up times and thus personnel requirements and costs. The screen casing angle with a wide adjustment range from 15.4 – 20° makes optimisation of the screening capacity possible. Special highlight: the simple and fast conversion from 3- to 2-way grit. The MSS 802(i) EVO can therefore be used to produce and discharge two or three final grain sizes and the conversion is fast and simple.
Operability and ergonomics for more comfort and safety
An intuitive plant control with automatic start reduces the risk of operating errors and saves learning times. All relevant functions can be operated from a safe distance, which offers high work safety. Further user-friendly aspects include very good access options and intelligent cleaning solutions, which minimise downtimes caused by maintenance. With all of these solutions, Kleemann placed the focus on the typical workday of users. This also applies to the standard series LED lighting, the optionally available extended premium lighting of work areas or the generously proportioned work platforms.
Efficient and precise process sequences for optimum material flow
An optimised material flow is a central aspect of all screening plants. Only if all components are tuned to one another can high productivity with minimised operating costs be achieved. With its new mobile screen for coarse elements, Kleemann demonstrates what screening plants of the latest generation can achieve. This includes a wide crusher discharge conveyor on which, like all of the other conveyors, the speed can be steplessly adjusted, as well as a large material transfer system to the screen deck for optimum utilisation of the screening surfaces. High discharge heights and thus higher stockpiles thanks to the optionally available extended crusher discharge conveyor and telescopic side discharge conveyors guarantee ideal processes on the building site.
It goes without saying that the new MOBISCREEN MSS 802(i) EVO can be operated through line coupling with all EVO and PRO crushing plants integrated in the process and safety system. Special application flexibility is provided by the stockpile probe required for the process coupling, which can be placed on any discharge conveyor of the plant.
PRO machines make the near impossible come true – grit in only two stages
In Schlag, in the Bavarian Forest, Berger Rohstoffe GmbH has been operating a granite quarry since 2020. This granite is crushed to road stone and grit in different fractions . The company was already working with a Kleemann plant train in a similarly structured quarry in the neighbouring Czech Republic. Due to this positive experience, a decision was also made in Schlag in favour of the mobile crushers, screens and stackers from Kleemann.
Machines for tough applications
The robustness, stability and efficiency of the crushers were of decisive importance. For Markus Penz, operating engineer and plant operator at Berger, the well functioning maintenance and spare parts supply concept of Kleemann and the Wirtgen Group also played a role. This machine service ensures a high machine availability and trouble-free processes. The mobile plants from Kleemann allow quarries to operate with a high rate of return because, even as extraction advances, the transport paths always remain short.
Kleemann plant train guarantees high productivity
The mobile PRO plant train has been in operation since August 2020. The core of the plant comprises the jaw crusher MOBICAT MC 120 Zi PRO and the cone crusher MOBICONE MCO 11i PRO. The screening plants MOBISCREEN MS 952i and MS 953i EVO and the stacker MOBIBELT MBT 20 supplement the plant train, which impresses in daily operation with its high productivity and cost-effectiveness (Figure 1). Hard granite is turned into grit for high-quality concrete and mixed aggregates are produced for anti-frost layers.
Only two crushing stages to produce grit
The desired grit sizes are produced from the loaded granite in only two crushing stages. In the pre-crushing stage, the grain shape is only altered to a slight degree; the second stage consists of crushing to the specified size. “Normally, this is almost impossible. But, before starting work, for test purposes we had material from the quarries tested in Kleemann’s own laboratory. After fine-tuning of the plant according to these parameters, we produce continuously to this high quality level”, explains Andreas Wagner, Kleemann special consultant from Wirtgen Germany. Markus Penz is extremely satisfied with the result. “Approximately half of the material is transferred to our concrete mixing plants. Their requirements are stricter than the applicable standards. This plant allows us to easily meet all our target specifications because it works even better than we thought.” (Figure 2)
Figure 2. The team from Berger Bau (from left to right: David Göttlich, Manager of the quarry in Schlag, Markus Penz, plant engineer and plant operator and machinist Josef Dankesreiter) during the handover of the PRO plant by Andreas Wagner, Kleemann special consultant from Wirtgen Germany. Photo: WIRTGEN
Stable processes thanks to line coupling
The complete plant train consists of five machines and operates as a line coupling. This means that automatic control stabilises the complete process. Each machine basically operates independently but forwards signals to the upstream and downstream machines in the event of malfunctions or overfilling. The feed control Continuous Feed System (CFS) also guarantees optimum utilisation of the crusher.
All components are loaded evenly. This is not taken for granted in stone processing where a natural product is to be turned into a standardised product. The stone crushes differently and there are fluctuations in the deposits: in the structure, due to the weather and the type of feeding. Output fluctuations are therefore normal. It is precisely these fluctuations that are balanced out by the optimised process thanks to line coupling in combination with the machine control system, the correct selection of machines and not least through qualified personnel. The automated tuning relieves the burden on the operators and harmonises the process.
The connection of all machines also guarantees safety: if an emergency-stop button is pressed anywhere on the plant train, all machines are safely stopped. This concept prevents damage or overload situations. All of this combined results in a high availability and output with low wear.
Operating concept with SPECTIVE increases safety
After delivery of the new plants, the three-man core crew in Schlag also had to familiarise themselves with operation of the mobile crushing and screening plants. They found this really easy because the crushing plants are equipped with SPECTIVE. SPECTIVE is an operating concept with an intuitive structure. It is started at the 12 inch touch panel (Figure 3). All data is displayed as values but also in image form. This means that the plant is also easy to operate by staff who are only deployed on rare occasions. Furthermore, the clearly arranged user guidance contributes to safety. “There’s not a lot you can do wrong during operation because the machine does not permit incorrect settings”, says Markus Penz.
Figure 3. The SPECTIVE operating system from Kleemann displays all data as values, and also graphically. This makes operation easier. Photo: WIRTGEN
Wirtgen Group Service concept guarantees high machine availability
After the first few months and experience from the Czech Republic, the team in Schlag realised that machine availability was an additional plus point. Instructions are short and concise for everyday work, but are very precise. A lot of tasks that go beyond the daily check can therefore be carried out single-handedly. This is guaranteed by the practical machine design that places the focal point on the needs of operators. (Figure 4)
Figure 4. Wide opening flaps and the practical arrangement of the relevant components reduce the complexity of the daily checks, maintenance and changing worn parts on the Kleemann machines. Photo: WIRTGEN
And if we ever need a Service technician, the specialists from Wirtgen Group are easy to reach. “We have competent contact partners on every level: in sales, service and spare parts supply. We are already familiar with this good co-operation because we have other devices and products from the other brands in the Wirtgen Group. Ownership of this plant train from Kleemann means that here in Germany we now have products in our fleet from all brands in the Wirtgen Group,” says Markus Penz.
Dual Power: sustainable stone production with electric drives
Kleemann machines with Dual Power have a module well along the path to sustainable stone extraction and processing. Berger Rohstoffe GmbH wants to produces in an environmentally friendly manner. Fossil fuels no longer meet contemporary standards in the long-term – also in quarries. Berger therefore ordered all components of the plant train equipped with the external power supply option. The screens can be driven, for example, either electrohydraulically or diesel-hydraulically. At present, the purely electric drive is used in the quarry in Schlag to operate the mobile screening plant MOBISCREEN MS 953i EVO using the power from the jaw crusher MOBICAT 120 Zi PRO.
In the long term, the company wants to convert the complete structure of the quarry to electric drives. Apart from the machine selection, photovoltaic systems are also used in many of their plants.
As a trusted partner of the mining industry, the Wirtgen Group offers mature and practical technologiesfor the mining and processing of raw materials. At Minexpo in Las Vegas(booth no. 8109, central hall), the Wirtgen Group will be presenting its field-tested 220 SM(i) 60-ton class surface miner for the first time on the North American continent (Figure 1).
Wirtgen Surface Miners and Kleemann Crushing and Screening Plants High-performance equipment with a long service life is essential when mining mineral deposits and processing natural stone. The rugged surface miners from Wirtgen and the crushing and screening plants from Kleemann are extremely reliable and cost-efficient machines for a whole range of tasks in the mineral extraction and processing industry (Figure 2).
Fig. 2. MOBISCREEN MS EVO screening plants from Kleemann impress with high productivity, good transportability, and optimal screening results in even the most challenging open cast mining scenarios – as at this iron ore mine in India.Photo:Wirtgen Group
220 SM(i) for Raw Material Extraction and Routing Operations With a cutting width 7 ft 3 in (2,2 m) and a cutting depth of up to 11.8 in (300 mm), the new 220 SM(i) surface miner is an ideal choice for the selective extraction of minerals, routing operations and infrastructure projects. A particular highlight of the 220 SM(i), which offloads extracted minerals in windrows, is its spacious ROPS/FOPS operator’s cabin. It can be heated or air-conditioned, and is soundproofed and isolated from vibrations. An operator-friendly multifunctional joystick controls all key functions of the machine.
Preview of the Successor to the 2500 SM Sales of a further surface miner are scheduled to begin at the turn of the year. The highlight features of the new 280 SM(i), the direct successor to the 2500 SM, include a slewable operator’s cabin. The industry-leading technological innovations onboard the 280 SM(i) work hand-in-hand to ensure high overall productivity and cost-efficiency.
Product Line Expansion Wirtgen will be adding more new models to its range of surface miners. The first of these will be the 260 SX(i), which is not designed primarily for traditional mining applications, but also for use in large-scale infrastructure projects such as the construction of railroads, drainage canals, freeways and highways, and the enlargement of tunnels.
Wirtgen Group Services: Expertise and Best Practices Are Essential Machine availability plays a key role in assuring productivity and profitability, especially in the mineral extraction and natural stone processing industries, where machines are often kept running night and day. In addition to premium technologies from Wirtgen and Kleemann, the Wirtgen Group offers a comprehensive range of services.
For example, a 360° solutions concept for projects, which, incidentally, also offers assistance with financing. Through its strong commitment to providing optimum support to customers through individualized, made-to-measure solutions, the Wirtgen Group has positioned itself as the ideal partner for the mining industry.
On behalf of the HeidelbergCement Group, Wirtgen GmbH, Windhagen/Germany, conducted a performance test with the 220 SMi 3.8 surface miner at a chalk quarry in Couvrot/France. The goal was to increase production output compared to the current mining method using a crawler dozer while simultaneously reducing operating costs.
During the demo, several tests were conducted to convince the customer that the smallest Wirtgen surface miner is a viable and more efficient alternative. To do so, the surface miner’s cutting performance, turning time, and fuel consumption were recorded, among other parameters.
Up until now, the company has used a bulldozer to break up the chalk in Couvrot, before a scraper loads the material into the hopper and transports it to a temporary storage facility. From there the chalk is transported to the adjacent cement factory, where it is immediately processed.
Since the pieces of rock mined by the dozer are relatively large, with a grain size of up to 80 cm, this mining method causes several problems at once. On the one hand, it creates an uneven surface that must first be leveled by the dozer so that the scrapers can be used to load the material in the first place – an additional, extremely time-consuming task. On the other hand, the coarse grain means that the scrapers require considerable energy and force to load the mined material. This primarily causes considerable traction issues for the scraper, which results, among other negative effects, in an extremely high level of wear and tear to the machine’s tires. As a result, two to three dozers are currently required per shift to level the excavated area and push the scrapers. In addition to the customer’s expected output of at least 500 m3/h, the objective was to eliminate the aforementioned problems with the help of the surface miner.
The 220 SMi 3.8 surface miner is capable of selectively mining raw materials at cutting depths of up to 350 mm and a uniaxial compressive strength of up to 35Â MPa. Thanks to its 3.8 m wide cutting drum designed specifically for soft-rock mining, the surface miner achieves maximum productivity at low operating costs, making the compact 220 SMi 3.8 perfect for use in small to large mining operations. During the performance test in Couvrot, cutting zones with a length of 150 m and 300 m as well as a width of around 40 m were first mined using the 3.8 m wide cutting drum. The drum was then replaced with a 2.2 m wide drum and tested for one more day.
According to the customer, the Couvrot region receives significantly more rainfall between October and April than in the summer months. Huge puddles make it difficult to mine the chalk and the moist material has a negative effect on further processing. These conditions were simulated at the beginning of the tests. The 220 SMi 3.8 had to perform a variety of cutting tasks in muddy and wet terrain. The machine also mastered this challenge without any loss in performance. All of Wirtgen’s surface miner models feature adjustable longitudinal and cross slopes, which ensures that rainwater drains off and keeps the working surface dry.
Even when cutting on slopes with a gradient of up to 16 %, the production output of the 220 SMi 3.8 remained high. The machine achieved a peak cutting performance of 1,400 m3/h. This represents an outstanding result for the customer, since most of the quarry’s mining areas are located on such steep slopes.
The fact that Wirtgen’s surface miner can easily handle the average rock hardness of 20 to 30 MPa was clear even before the tests began. After all, it is designed for rock with a compressive strength of up to 35 MPa. Some areas of the quarry contain deposits of blue marl with a hardness of up to approximately 40 MPa. Another challenge for Wirtgen’s miner that the 220 SMi 3.8 mastered with an advance rate of 5 to 10 m/min.
In the final and probably most important test, the surface miner was used for an entire shift at the quarry. As part of a fleet with three scrapers and one dozer, the 220 SMi 3.8 cut at two cutting depths of 20 and 30 cm (Figure 1). Thanks to its powerful cutting drum and an engine output of 963 PS at a weight of 59,000 kg, the miner was able to produce significantly smaller and more uniform grain sizes than the dozer. The advantage of this is that the material cut smaller is easier to load than the large pieces of rock, so the scraper and dozer need less power to load the scraper hopper. In addition, the milled material lies flat on the surface, which means it no longer needs to be leveled with the dozer, saving additional time and therefore cutting costs. In addition, the surface miner produces level surfaces that make it easier to load the scraper and provide stable road surfaces for fast material transport. Thanks to the level haul roads, tire wear can also be reduced.
After completing the test, the quarry operator was more than satisfied with the results achieved by the 220 SMi 3.8. The surface miner far surpassed the target output rate of 500 m3/h. In fact, at times the machine was able to extract almost three times the specified amount of chalk per hour.
Due to its outstanding cutting performance and its production of fine grain sizes and flat surfaces, the operator no longer needs to use a dozer, which increases output and reduces costs at the quarry. In addition, the flat surfaces reduce traction problems and scraper tire wear. Since the chalk is pre-crushed by the 220 SMi 3.8 at the quarry, further costs resulting from the use of crushers can be saved during further processing at the cement factory.
Indian company uses highly productive and extremely reliable Wirtgen 220Â SM 3.8 surface miner, which specializes in soft rock mining, in a coal mine in the Indian state of Odisha.
India has extensive coal reserves and uses them as the country’s most important source of energy, covering about half of its primary energy needs with coal. One of the country’s largest coal mines, the Bhubaneswari coal mine, is located near the town of Talcher in the eastern Indian state of Odisha, where coal has been mined since the 1990s. The Indian company Bhubaneswari Coal Mines Ltd. (BCML) has operated the open-cast mine since 2011, and successfully uses Wirtgen surface miners here.
Safe, 24/7 Operations
Mining operations at the Bhubaneswari coal mine are conducted 24 hours a day to permanently supply the nearby coal-fired power plants with the raw materials they need to generate electricity. As a result, the company mines more than 25 million tons of coal annually with a uniaxial compressive strength of up to 35 MPa. At the open-cast mine, the company completely refrains from blasting and drilling – instead, BCML relies on the safe method of cutting the soft rock. Bairagi Sahu, Associated Vice President BCML, is highly satisfied with the 7 machines: “When it comes to performance, the Wirtgen surface miners are simply the best on the market. At our mine, we sometimes cut up to 1,800 tons of coal per hour with one surface miner.”
In addition, eliminating the need for drilling and blasting and instead using surface mining technology results in a number of other benefits. First of all, it increases the safety of open-cast mining by eliminating the need to store and handle explosives. Enhanced slope stability and therefore less rockfall also contribute to greater safety. Surface miner technology also eliminates the need to close the mine for blasting, which delays production. In addition, mine operators no longer need to spend time obtaining the required permits, hiring certified blasters, or compiling the associated documentation.Â
Optimized Exploitation of Deposits
Mining with Wirtgen surface miners also offers considerable financial benefits. The flat surfaces created during the mining process serve as stable roadways that facilitate fast truck haulage. This increases the transport capacity of the entire truck fleet, and the quality of the road surface even reduces wear and tear to each truck’s tires, frame, and suspension, allowing the operators to use standard trucks. The resulting reduction in transport costs helps mining companies lower production costs per ton of material.
In contrast to drilling and blasting, the use of surface miners makes mining vibration-free and significantly reduces noise and dust emissions. As a result, the material can be mined close to industrial sites and other infrastructure facilities such as pipelines, railroad tracks, or high-voltage lines that cannot be exposed to vibrations. This improves the exploitation of the deposit and with it, the overburden-to-coal ratio, allowing the operator to generate additional revenues.
The 220Â SMÂ 3.8: An Intelligent Solution for Soft Rock
The only requirement for companies to fully leverage the benefits of the surface mining process is to use intelligent machine solutions. The 220 SM 3.8 (Figure 1) is one such solution that has demonstrated its exceptional value at mines around the world, including the Bhubaneswari coal mine. This powerhouse with an operating weight of 58 t is propelled by a robust Cummins diesel engine with an output of 708 kW. Thanks to high-pressure injection and intelligent engine management, the engine is extremely fuel-efficient. At the same time, the diesel tank with a capacity of 2,300 l makes it possible to operate the machine around the clock with only one stop to refuel per day, resulting in unrivaled productivity. A cooling system with a demand-driven fan speed also helps to reduce fuel consumption and at the same time reduces noise emissions.
A Windrowing Specialist
The 220 SM 3.8 is designed for mining all types of soft rock. This is particularly evident in the design of the 3.80-meter-wide cutting drum. As such, high, narrow holder bases on the drum ensure that the material flows smoothly while requiring minimal energy. In addition, the shape of the holders in combination with the arrangement of the cutting tools minimizes the amount of fines in the material, which is continuously deposited in a windrow directly behind the machine. “With this mining method, we can clearly see the quality of the coal due to the difference in color between the coal and the light-colored overburden, allowing us to mine the material cost-effectively,” says Om Prakash, Chief Operating Officer, BCML, describing one of the key advantages of the method.
Reliable, Around-the-Clock Output
In open pit mining, nothing is more important than the reliable availability of the machines. As a result, all of the 220 SM 3.8’s components are designed for extremely demanding open-cast mining applications. For example, additional filters in all of the machine’s circuits and a pressurized hydraulic reservoir ensure maximum purity in the hydraulic system for smooth operations. The clean oil in turn extends the service life of the downstream components, which also contributes to higher machine availability. The components’ long service life and the miner’s minimal downtime ultimately result in greater productivity and cost-effectiveness.
Unparalleled User-Friendliness
The 220 SM 3.8 also stands out in terms of occupational safety. The standard ROPS-FOPS operator’s cabin features additional soundproofing and vibration isolation, allowing the operator to work with maximum focus for many hours without the risk of fatigue. The ergonomically designed and clearly arranged controls are integrated into the armrests of the driver’s seat, and all of the machine’s key functions are logically incorporated into the multifunctional joysticks. This means that the operator can operate the machine intuitively in just a few steps and fully concentrate on high-precision mining.
For optimum visibility, the fully air-conditioned, spacious cabin features generously-sized windows and is positioned so that the operator always has a clear view of the cutting edge. An optional camera system also gives the operator an excellent overview of the work area, even behind the machine. In short, ideal conditions for productive operations (Figure 2).
Fig. 2. One highlight of Wirtgen’s 220 SM 3.8 is the spacious ROPS/FOPS operator’s cabin. It can be heated or air-conditioned and is soundproofed and isolated from vibrations. All of the machine’s key functions have been integrated into the multifunctional joystick. Photo: Wirtgen
The 220 SM 3.8 is also designed to be easy to service and maintain. All of the maintenance and service points are easily accessible from the ground or inside. The walk-in engine compartment also makes it possible to quickly and easily inspect the engine. The machine’s air, fuel, and hydraulic oil filters are also directly accessible. Ultimately, the intelligent maintenance concept also results in higher machine availability.
The Bottom Line: An All-Around Impressive Machine
The new 220 SM 3.8 has succeeded in fully meeting the operator’s expectations in daily use at the Bhubaneswari coal mine: “The Wirtgen surface miner has proven itself across the board at our mine,” says BCML Chief Operating Officer Om Prakash, summing up Wirtgen’s latest innovation on an extremely positive note.
A total of 120 exhibits, including 18 world premieres and 25 innovations as well as six interactive technology demos: the Wirtgen Group’s booth at bauma (Figure 1) was packed with leading machine and application technologies from Wirtgen, Vögele, Hamm, Kleemann, Benninghoven, and John Deere.
The trade show in Munich clearly demonstrated that the complementary product ranges of the Wirtgen Group, Windhagen/Germany, and John Deere are a perfect fit. Visitors were not only impressed by the numerous possible applications resulting from the synergies between the products, but also by the two companies’ unified presence, which underscored their common bond and their intention to continue to grow together in the future.
The 622GP motor grader, which John Deere is launching on the European market together with the 672GP, was met with great interest. The Wirtgen Group’s sales and service network in Germany and France is handling the sale of these products – a prime example of how customers can already benefit from premium products and services from a single source, which perfectly fits the “SmartSynergies and Innovations” theme of the group’s presence at bauma this year. SmartSynergies refers to how the specialized product brands Wirtgen, Vögele, Hamm, Kleemann, and Benninghoven offer unparalleled solutions for every road construction application that complement each other perfectly – and are further enhanced by the synergies created as a result of the Wirtgen Group being part of John Deere.
With its 18 world premieres and 25 innovations, the group also underscored its position as the innovation driver and technology leader in the road construction sector. In addition to the six technology demos, visitors were clearly interested in the new machines. As a result, the rush to view the new products – such as the intelligent Wirtgen W 210 Fi cold milling machine with Mill Assist, the impressive Vögele SUPER 3000-3(i) large paver with 18 m screed, the new Hamm HP series of pneumatic tired rollers, the rugged Kleemann MOBICAT MC 120 Z PRO jaw crusher for demanding mining operations, the environmentally friendly Benninghoven TBA asphalt mixing plant with hot gas generator, and, of course, the entire range of John Deere construction equipment – did not let up during the entire event.
West African Guinea is known for possessing the largest reserves of high-quality bauxite in the world. This potential has prompted the country to continually expand its bauxite mining sector in recent years, making substantial investments. Wirtgen surface miners are playing a decisive role in this development process, as many of the country’s bauxite mining operations rely on Wirtgen’s technology as their standard extraction technique.
The Wirtgen GmbH, Windhagen/Germany, supplies surface miners in a variety of performance classes for the selective mining of raw materials, such as coal, limestone, bauxite, gypsum, salt and phosphate. In addition to mining, these machines can also carry out routing operations for the construction of mining service roads and railway tracks, the rehabilitation of roadways and installation of tunnel floors. The range of applications further includes the precise cutting of trenches and channels as well as surface leveling.
In 2001, the first Wirtgen surface miner was commissioned in a mine close to Kindia, a small town 120 km from the capital, Conakry. At this time, drilling and blasting was the main bauxite mining technique in use. Since then, however, the process has shifted to the more economical, safe and environmentally friendly surface mining, and today Wirtgen surface miners extract 100 % of the ore. Since 2001, the Wirtgen technology has proven its additional benefit to the growing bauxite mining industry in Guinea, where 25 Wirtgen machines are currently in operation.
The most commonly used models for bauxite mining in Guinea are the 2200 SM and the 2500 SM. The first is compact yet powerful, with a 2.2 m long cutting drum and 708 kW of engine power. It is able to cut rock with unconfined compressive strengths of up to 50 MPa, ideal for medium-sized mining operations. The larger model, the 2500 SM, guarantees higher production rates and offers a cutting width of 2.5 m, 783 kW of engine power and can economically mine rock with an unconfined compressive strength of up to 80 MPa.
Both models demonstrate their advantages in both productivity and product quality, guaranteeing lower production costs per ton compared to conventional mining. On average, 1.25 Mt/a of bauxite are extracted with the 2200 SM and 3Â Mt/a with the 2500 SM. These figures are achieved because the machines work 24/7.
The figures are all the more impressive considering Guinea’s humid climate, with a monsoon season that lasts from June to November and is a major challenge for mining companies. During periods of heavy rainfall, cutting-to-ground or drilling and blasting expose the ore to precipitation, resulting in high transportation costs due to the ore’s high moisture content resulting in other negative downstream effects.
Wirtgen surface miners, which are equipped with a discharge conveyor, minimize such climactic effects by cutting and crushing the material with a special cutting drum and placing it alongside the machine (sidecasting) ensuring constant productivity while minimizing the environmental impact (Figure 1). The use of a surface miner also has a positive effect on water management in an opencast mine. The cut surfaces are leveled and can be cut at an angle. This further improves drainage and reduces water seepage into the ground.
Fig. 1. Wirtgen’s 2500 SM sidecasts the mined material, producing high windrows. The leveled sidecast material is clean, stable and ready to be transferred onto trucks with wheel loaders or excavators. Photo: Wirtgen
During side-casting, Wirtgen surface miners leave high stockpiles allowing a superb bucket fill (Figure 2). This protects most of the mined material from the rain and allows gravity to drain the piles. The major cost factor in opencast mining is haulage. Mining with Wirtgen surface miners produces level surfaces that serve as stable roadways, supporting the rapid transport of material. This increases the transport capacity of the entire truck fleet. Even the wear on tires, frame and suspension is reduced thanks to the quality of the roadways, also allowing the use of standard on-highway trucks. As a result, reduced transportation costs allow mining companies to achieve lower per-ton production costs.
Mine operators benefit from several cost reductions when using surface miners. Erik Zimmermann, Product Manager for Surface Miners at Wirtgen, explains: “Our machines allow efficient extraction of material from mines that could not be economically exploited with traditional techniques, creating added value for the industry. For the mining companies, this translates into significant financial advantages for mining and processing.”
By using surface miners instead of drilling and blasting, raw materials can also be extracted effectively in the vicinity of residential areas, public roads, villages, rivers or other infrastructure, e. g., pipelines or power lines. It is also possible to mine resources located in buffer and safety zones, maximizing bauxite yield within the concession area, generating significant additional revenue for the mine.
In most cases, the planning and execution of blasting operations is associated with considerable effort, high costs and regulatory restrictions. In fact, eliminating drilling and blasting relieves the people responsible of a number of challenges. The Guinean mine operators using surface miners no longer need to spend time obtaining the required permits, hiring certified blasting personnel or compiling the relevant documentation. What is more, dispensing with drilling and blasting has a very positive impact on public opinion, meaning that opencast mining operations can gain wider acceptance.
In addition, Wirtgen machines enable mining companies to improve material quality. The material size produced by these surface miners is ideal for shipment by truck and rail, eliminating the use of the primary crushers commonly used when drilling and blasting.
As Africa’s top bauxite producer, Guinea has increased its production from year to year. In addition to the customized machine equipment, Wirtgen is providing factory-level local customer support through an office in Conakry which offers complete on-site services such as technical assistance and service contracts using qualified personnel from Wirtgen’s brand headquarters in Germany. Technical support is provided directly at the mine. The company’s innovative logistics program ensures a smooth provision of original spare and wear parts. Wirtgen experts are also able to support customers around the clock with customized, on-site project planning specially tailored to their needs.
PJSC Ivano-Frankivskcement (IFCEM) produces clinker and 300 other cement and gypsum products. The raw material for the cement plant comes from a deposit located 15 km to the north. The Carpathian mining area is rich in sedimentary rocks such as limestone, marl and gypsum.
For years, the material was extracted by drilling and blasting and then wet-processed into clinker in the cement plant. In a move to increase productivity and reduce costs, IFCEM became the first cement plant in the Ukraine to initiate the transition from the wet to the dry process, a measure which was accompanied by an optimization of the mining method for material supply.
The dry process is now considered the preferred method for clinker production as it reduces fuel consumption per ton of material. This in turn has a positive effect on production, costs and the environment. For an optimal drying process, the material from the quarry should only have a low moisture content so that it can be crushed in a dry crusher, ground to powder in the raw mill and burnt in the rotary kiln without further pre-treatment.
In order to ensure that the material extracted from the quarry is as dry as possible, a radical change in the mining method was necessary. Meanwhile, the previous use of explosives for limestone mining was having a detrimental effect on neighboring residential areas due to the noise generated and the ground vibrations. IFCEM found the solution in Wirtgen surface miner technol-ogy. In 2012, the company purchased a 2200Â SM, in 2015 a second, identical model and in 2017 a 2500 SM.
By gradually phasing out the drilling and blasting operations, the surface miners progressively reduced the time and cost involved in pre-crushing and post-crushing the material and also made it possible to redesign the deposit (Figure 1). By ensuring a defined slope of the surface with the aid of the Level Pro automatic leveling system, the surface miners created the conditions for efficient dewatering.
Compared to drilling and blasting, this allows much drier raw material to be mined and the material can enter the plant’s drying process without any further treatment. Thanks to the redesign of the mining area with the surface miner, the exploitation of the deposits has also been increased, because now even previously unused areas can be worked and additional material extracted.
The increased mining volume thus also had a major influence on the selection of the third machine model. After the impressive results of the smallest Wirtgen surface miner 2200 SM with a 2.2 m cutting drum and a cutting depth of up to 300 mm, the technical management of IFCEM now opted for the even more powerful model, the 2500 SM.
Together, the three Wirtgen surface miners generate a daily output of 7,000 t, which also leads to optimum utilization of the cement plant. The 2500 SM has made an important contribution to this, as well as to increasing production in the limestone quarries, where the material has a uniaxial compressive strength of between 20 and 70Â MPa depending on its depth. The 2500Â SM, which has already clocked more than 4,500Â h, is equipped with a 2.5 m-wide cutting drum fitted with cutting tools on an HT 15 quick-change tool-holder system. HTÂ 15 reduces the time required to replace the tool-holder from 90 to 15 min compared to conventional welded tool-holder systems.
The 2500 SM, which can remove material up to 650 mm deep, extracts the material in Ivano-Frankivsk up to a depth of 40 to 45 cm. Depending on the rock hardness, the surface miner achieves a feed rate of 5 m/min and a grain size of 0 to 100 mm. Depending on the hardness of the rock, the entire tooling is replaced at intervals that vary between 200 and 500 h based on the machine’s field of application.
Since its market launch, the 2500 SM has proven its performance and flexibility worldwide, as it can be used for the selective mining of raw materials with uniaxial compressive strength up to 80 MPa and in special cases even higher. The surface miner cuts, crushes and loads the rock in a single operation. Depending on the application, the material can either be loaded directly into trucks via the 11.3 m long, slewing discharge conveyor of the miner (Figure 2), deposited laterally or as a windrow between the machine’s crawler tracks. The 2500 SM is powered by a 783 KW engine and features precise mining of the useful minerals thanks to the Level Pro leveling system integrated into the machine’s control system.
Fig. 2. For direct loading, Wirtgen surface miners and trucks generally travel in parallel in the same direction. However, the mine logistics in Yamnytsia required the truck to be positioned facing the opposite direction to the 2500 SM during loading. Thanks to the optimum visual concept of the surface miners, the operator was also able to load the material safely under these conditions. Photo: Wirtgen
The operator sits in a spacious, sound- and dustproof, air-conditioned cabin. A video system with several cameras gives the operator a complete overview during the extraction process, ensuring maximum safety.
According to Yaroslav Nesterovych Voznyak, Technical Manager of the deposit, the surface miners, especially the 2500 SM, have had a positive influence on the production cycle in the quarry and thus also in the cement plant: “The purchase of the Wirtgen surface miners made the transition from drilling and blasting to a safe mining process easy to implement. In addition to the environmental and production benefits, the surface miners have proven to be the best solution, especially in terms of cost efficiency and economical operation. The grain size of the material produced is ideal for the cement plant. This is why our fleet of surface miners will grow. We are already preparing a further mining area with a volume of around 180 mt of material, which we want to mine with our Wirtgen surface miners”.
Further information/Weitere Informationen: WIRTGEN GmbH www.wirtgen.com
Mine operators for some time now have been increasingly turning to an alternative to conventional rip-and-stack or drill-and-blast coal mining: the use of surface miners. Diverse studies and tests show that surface miners offer considerable advantages in terms of both economic efficiency and the final product.
The main advantages of Wirtgen surface mining technology include the following:
• selective mining; • avoidance of blasting; • cutting, crushing and loading in a single operation; • maximum exploitation of deposits; and • reduced transport costs.
Wirtgen GmbH, Windhagen/Germany, supplies surface miners in a variety of performance classes for the selective mining of commodities, such as coal, limestone, bauxite, gypsum, salt and phosphate (Figure 1). In addition to mining, these machines can also carry out routing operations for constructing roads and railway tracks, rehabilitating roadways and installing tunnel floors. The range of applications further includes the precision cutting of ditches and channels as well as surface leveling.
In collaboration with RWTH Aachen University, Wirtgen conducted a study in a black coal mine in Queensland/Australia. This article will explore the advantages that surface miners offer in coal mining based on the results of this study.
The 4200 SM surface miner was integrated into an ongoing operation for the selective mining of coal and interburden. Previously defined targets were checked regularly to determine if they were being met.
Compared to the three mining machines used at the mine previously, using a surface miner significantly reduced noise emissions.
Mining with the 4200 SM likewise has a positive impact on dust emissions. In contrast to the dozers and wheel loader – all of which generate considerable quantities of dust that impact the work environment – the dust produced by a surface miner is contained in the cutting drum housing. A dust suppression system comprising an integrated water spray system also helps to additionally reduce and bind the dust.
An analysis of the two mining methods further demonstrated that fuel consumption is about 79 % lower – and therefore also CO2 emissions – with surface miners than when using the conventional method. The lower number machines in use additionally has a positive effect on risk management, because fewer machines mean a reduced risk of accident at the mine.
The surface miner’s anti-vibration cabin offers better ergonomics and optimized working conditions for the machine operator. The vibrations generated in the 4200 SM were rated as “low” according to Australia’s AS 2670-2001 standard, while the ratings for the conventional systems were higher.
Coal seams generally are of varying thickness and separated by interburden layers. Precisely separating the various materials is of tremendous importance if coal is to be mined as cost-efficiently as possible, because it significantly reduces processing costs. Another major cost driver in this regard is the percentage of fines, because they are much more costly to process than coarse material.
For the study, a total of 100 samples (30 t each) were analyzed during operation of the surface miner to determine the particle size distribution. Those samples were compared with similar ones taken from the conventional mining equipment and identical mining fields. Significant advantages emerged when working with the surface miner, which produced 14 % fewer fines at grain sizes of less than 2 mm compared to the conventional mining system. The portion of fines to be processed dropped by 22 % at grain sizes of less than 1 mm and even by 36 % at grain sizes of less than 0.5 mm. Further savings were achieved by significantly reducing the quantity of oversize. Only 17 %, e. g., of the material mined by the surface miners had to be crushed compared to 26 % for the dozers.
The deposit analyzed in the study contains siderite intrusions, particularly at the boundary between seam and interburden. In the conventional process, this frequently led to difficulties, because the siderite intrusions are very hard and therefore difficult to mine. As a result, dozers frequently produce oversized siderite boulders that cause blockages in the crusher. This is not the case when mining with a surface miner.
In addition, working with a surface miner reduced coal mining losses and dilution of coal in the mine. This leads to more product, hence increased turnover and even an improved exploitation of the deposit and thus a better stripping ratio.
Fig. 2. Wirtgen surface miners can load material via stable conveyor systems directly into trucks or dumpers in a single operation. The material can also be deposited in windrows between the crawler tracks or placed alongside the machine. // Bild 2. Wirtgen Surface Miner können das Material über stabile Fördersysteme in einem Arbeitsgang direkt auf SKW/LKW verladen. Auch das Ablegen des Materials zwischen den Fahrwerken als Schwade (Windrowing) sowie das seitliche Platzieren neben der Maschine ist möglich. Photo/Foto: Wirtgen
Wirtgen surface miners can cut, crush and directly load material onto trucks or dumpers in a single operation (Figure 2). This saves time and the additional cost of purchasing machinery and fuel. Working with the 4200 SM in the Australian mine resulted in a 79 % reduction in fuel consumption per cubic meter of mined material. Labor costs were reduced by 60 % and mining unit costs per ton were reduced by 60 % compared to the conventional mining method.
The score card clearly demonstrated that – when the entire process chain is taken into consideration – mine operators benefit from tremendous cost reductions when using a surface miner. These reductions are not only a result of easier processing. The smaller number of mining machines and reduced manpower described above and the avoidance of additional costs for transporting and processing waste rock also contribute significantly to the good overall score achieved by the surface miner.
Not all benefits that result from the surface miner were part of the conducted study. Additional benefits are described below.
With surface miners, drilling and blasting can be eliminated. In other words, even commodities located in the vicinity of residential areas, public roads or other infrastructure can be effectively mined. It is likewise possible to mine resources located in buffer and safety zones.
In most cases, planning and execution of blasting work is associated with considerable effort, high costs and regulatory restrictions. In fact, eliminating drilling and blasting relieves the people responsible of a number of challenges. Mine operators no longer need to spend time obtaining the required permits, hiring certified blast personnel or compiling the associated documentation. Furthermore, getting rid of drilling and blasting has a very positive impact on public opinion, meaning that opencast mining operations can proceed without causing friction in a community.
The following are further advantages of eliminating drilling and blasting:
• enhanced safety at the mine because no explosives need to be stored; • no boulder handling necessary; • less impact on the environment (vibration, dust and noise); • no interruptions for blasting (production delays); • improved slope stability; • reduced rockfall; and • better recultivation of embankments.
The use of a surface miner also has a positive effect on water management at an opencast mine. The cut surfaces are levelled and can be cut at an angle. Drainage is further improved as a result and water seepage into the ground is reduced.
The major cost factor in opencast mining is haulage. Mining with Wirtgen surface miners produces level surfaces that serve as stable roadways, supporting the rapid transport of material. This increases the transport capacity of the entire truck fleet. Even wear on tires, frame and suspension is reduced thanks to the quality of the roadways, making it possible also to employ standard on-highway trucks.
In recent years, Wirtgen has conducted several large-scale field tests on particle size distribution and ROM material degradation. In these studies, coal and sedimentary ore from eight different pits were analyzed to determine their particle size distribution. Some 8,000 t of material were screened to compare the material produced by surface miners with that extracted by conventional mining methods.
All of the studies illustrate that using Wirtgen surface miners delivers compelling improvements in final product quality, cost-efficiency, environmental protection and safety. In order too fully exploit the surface miners’ profit potential an analysis should be conducted when starting the planning of a mining project.
