Phosphate Mining in the Northern Dimension
Sub-level caving with electric-powered LHDs and drill rigs has helped Apatite JSC stabilize operations in the Kirovsk area of Russia
By Kyran Casteel, European Editor
A part of the PhosAgro concern, Apatite JSC operates mines and process plants located in the Murmansk Region of northwestern Russia, adjacent to Finland and Norway. The main underground mine uses a sub-level caving method derived from that developed at the Kiruna iron ore mine in northern Sweden; it also relies on Sandvik Mining and Construction drilling, loading and ore haulage equipment fabricated in Finland. The drilling fleets at the open-pits of Apatite JSC also include Sandvik drilling rigs.
Apatite JSC at Eighty
Apatite JSC is headquartered in Kirovsk, a town of about 30,000 inhabitants located in the Khibiny Mountains of the Kola Peninsula that is now also a popular ski resort. The company, which is celebrating its 80th anniversary in November 2009, extracts apatite-nepheline ore from mines around Kirovsk and separates the apatite and a nepheline concentrate at two processing plants.
Nepheline syenite mineralization was reported by Ramsay and Har in 1894, but detailed exploration started not long after the revolution. The deposits occur in alkali syenites within igneous rocks of the Khibiny massif. This domed complex, about 370 million years old, is approximately 40 km in diameter. The mineralized occurrences comprise several intrusive phases and within the 1-km-thick secondphase of the apatite-nepheline syenite there is a 100-m-thick, 11-km-long arc of ijolite-urtite; the apatite nepheline occurrences are associated with this arc. The deposits dip 35° to 70° and contain 10%- 80% nepheline, 15%-75% apatite, 1%- 25% impurities, and 5%-12% sphene, titanomagnetite, and feldspar.
A single apatite deposit, lying within +1,050 to –650 m above/below sea level, contains the Kukisvumchorr, Yuksporr, Apatite Circus and Rasvumchorr Plateau orebodies. The Koashva and Nyorkpahk orebodies are the southeastern part of the ore zone and this future mining territory features challenging mining and geological conditions. At Kirovsky the main deposits mined are Kukisvumchorr, Yuksporr and Rasvumchorr. The Rasvumchorr underground mine extracts ore from the Apatite Circus, the Tsentralny (Central) open-pit exploits the Rasvumchorr plateau orebody and the Vostochny (East) mine comprises open-pits at Koashva and Nyorkpahk. Four other orebodies in the region have been proven and included in the state reserve. They contain 3.5 billion mt, including a government reserve of 1.4 billion mt. The Kuelporr deposit has also been thoroughly explored and is included in the public register.
Research on processing apatitenepheline ores made the recovery of concentrated nepheline, aegirite, titanomagnetite and sphene as well as apatite possible. The national importance of this massive natural resource imposes obligations on the Apatite company regarding the exploration of the ore deposit and planning of its development for many years ahead.
To achieve comprehensive utilization of the raw materials, various technologies were used. The plant consumed a considerable amount of electric power to provide reliable operation in the harsh climatic conditions— winter temperatures can be as low as -40°C and snow may fall from August to June. Electric-powered machines are used for loading in the majority of the open-pits, as well as for underground drilling, ore loading and transport. In addition, electricity powers the railway linking the mines to the process plants.
During World War II, when Germany invaded Russia, most of Apatite’s production equipment was moved to the Middle Urals and to Kazakhstan. Only a few facilities kept on working with the pilot chemical plant in Kirovsk and a part of the Kirovsky mine supplying defense requirements. The order to resume production of apatite concentrate for agriculture came before the end of the war and apatite production restarted in spring 1944.
In the post-war period the state’s need for phosphate fertilizers grew as the national economy recovered. To satisfy these demands new fertilizer plants were built and Apatite increased concentrate output. In the mid-1950s two new underground mines, Yuksporrsky and Rasvumchorrsky, were built. The ANOF-2 processing plant in Apatity started operation in 1963. In 1950, Apatite produced 1 million mt of apatite concentrate, by 1967 the output rate had grown to 9 million mt/y. The Central open-pit mine on the Rasvumchorr plateau was opened in 1964. As It lies at an altitude of 1,000 m above sea level the ore could be loaded on to railway wagons running along already disused drifts. In 1968, the whole operation was called S.M. Kirov’s Apatite Combine.
The precipitous transition from the USSR’s central economic planning to a Russian free market led to a sharp and substantial decrease in domestic demand for both fertilizers and apatite concentrate in the early 1990s. For Apatite JSC, common economic difficulties were complicated by the necessity of operating assets at far below their rated capacity. Besides, Apatite JSC is a city-forming enterprise, compelled to maintain and govern the municipal engineering and infrastructure of Kirovsk and Apatity. As well the state terminated financing for capital investment so it became impossible to rationalize or modernize the mining facilities to any significant extent. By 1994, apatite concentrate output had fallen to 6 million mt/y and the very existence of the enterprise was in peril.
The need to secure massive investment to maintain apatite output from the Kola Peninsula was a main factor in the creation of large, well-financed holding companies to manage Russia’s phosphate fertilizer industry. The Apatite enterprise was reorganized as an open joint-stock company and became a part of PhosAgro while the apatite-magnetite-baddeleyite operation in Kovdor was taken over by Eurochem JSC. PhosAgro has three main fertilizer manufacturing subsidiaries—Cherepovetsky Azot, Balakovskiye Mineralniye Udobrenia and Ammophos—producing granulated phosphorus- containing fertilizers (monoammonium phosphate, diammonium phosphate), ammonium polyphosphate solution, complex nitrogenous phosphatic fertilizer (NP) and complex fertilizers (DAFK, NPK), as well as ammonium nitrate.
According to a company report, the years 1996–1997 can be regarded as the watershed in the recent history of Apatite JSC. A concept for strategic development was built up based on an analysis of the raw material situation and on the condition of the mining and processing facilities. The options determined by this exercise were used as a basis for the technical-and-economic assessment program Enterprise Optimal Development Until 2005 and Long-Term Development, which was formulated by a group of technical institutes (NIUIF, Giproruda, Mehanobr-Engineering, NIIGiprohim). The execution of this program helped Apatite JSC to overcome the critical situation, stabilize its operations and begin production development.
By 2007, 600 million m3 of overburden had been removed, more than 3 billion mt of rock mined, and more than 1.6 billion mt of apatite-nepheline ore extracted. Processing had yielded approximately 600 million mt of apatite concentrate and 60 million mt of nepheline concentrate.
Strategic planning is the keystone of an engineering policy for exploiting the more than 2 billion mt of ore still available in the 10 explored orebodies being exploited by four mines. This planning must overcome a number of problems arising from the extent of previous mining activity and the lack of investment in the early 1990s. Due to the increasing depth of mining operations, the rock transfer distances are longer, the overburden ratio is higher and the P2O5 content of ore extracted is lower. Today, the production of 1 mt of apatite concentrate consumes 1.3 times as much ore as required 20 years ago, while the ratio of the rock mined to the end product yield has changed even more noticeably: it is now 2.3 times higher. Overall, the extraction and transportation of ore make up 50% of Apatite JSC total costs.
The grave reserves situation of the Central and other open-pits also affects today’s mining options. Ore from the Rasvumchorr Plateau, exploited by the Central open-pit, was typically twice as cheap as ore from any other mine. From 1980 to 1990 this mine yielded 23 to 28 million mt of ore annually. Currently, the same amount of ore is produced in aggregate by four Apatite JSC mines. In 1986, approximately 70% of the total rock output came from the open-pits although the proportions of booked reserves suitable for surface and underground mining were 25% and 75%, respectively. Apatite reports that, as of January 1, 1994, the open-pit boundaries contained only 18% of total reserves, but by January 1, 2009, only 10% of the reserves remained available for surface mining. Compounding the effects of this resource reduction, during the past 10 to 15 years the depth of mining operations increased by 150 m to 200 m and the horizontal area of the orebodies decreased considerably, which could not but affect the ore extraction efficiency figures.
Ore enrichment operations account for 30% of the company’s costs. As well as being affected by the rising cost of electricity, the crushing and reduction of ore has also become more expensive, because the ore grade has fallen and the ore structure has changed. Two processing plants deliver two apatite concentrate grades: Standard with 39% P2O5, and high quality concentrate or Super. Production of Super started at the ANOF-2 processing plant in 1996 and at ANOF-3 four years later. The nepheline concentrate is used as a raw material for producing alumina and in cement, soda and potash production. It can also be used by the glass and ceramics industry. The Central Lab carries out scientific and experimental work on apatite-nepheline ore applications.
The company must also operate and maintain extensive facilities for stepping down the electrical power supply from 150 kV to the 6-kV operating voltage. There are 19 main substations, over 270 km of highvoltage power lines and hundreds of kilometers of 6 kV power lines.
Furthermore, Apatite JSC owns a large railway transport system: about 300 km of track and 16 stations, 500 dump cars, 30 electric locomotives and 22 diesel locomotives, which must be kept as efficient as possible. In addition to the necessary railway and road vehicle workshops, there are more than 20 other auxiliary repair workshops. And today, of course, much more is spent on environment protection measures: in total, RUR90-100 million annually.
Creating the 21st Century
Apatite JSC works out its middle- and longterm development concepts on the basis of the Feasibility Study into Optimal Development of Corporation in Period up to 2020 and Future Prospects for Period up to 2050, which was completed in 2000. This study determined the optimal apatite concentrate production level as 8 million mt/y. This level of output can be achieved by the existing ANOF-2 and ANOF-3 process plants and requires the annual extraction of a total of 28 to 30 million mt of apatite-nepheline ore by four operating mines.
The underground mines are situated next to Kirovsk and to a natural lake that is about 380 m ASL. Although Kirovsk is only 5 km from the Central mine in a straight line and the East mine is only 6 km from the city, the total road links are about 40 km longer because of the mountainous terrain. As mentioned above, the mines are connected to the process plants by the company’s electric railway system. The ore trains usually consist of 25 x 104 mt wagons. A significant portion of the track in the mining area is underground, for instance downstream of the Rasvumchorrsky mine and under the Central openpit, so ore hoisting can be minimized.
Kirovsky and Rasvumchorrsky are old, complex operations, which have been undergoing considerable modification since the mid-1990s. Now they are intended to achieve maximum underground mine production rates of perhaps 18.5 million mt/y by 2015. The underground output increase will compensate for the cessation of mining in the Central open-pit and one of the sites at the East mine. The development program provided substantial investments, for instance RUR2,472 million ($84 million) in 2007 and RUR7,249 million ($247 million) in 2008. Consequently, the underground mines’ contribution to total ore output has gradually increased, from 40% (9.1 million mt/y) in 1999 to 70% (14.3 million mt/y). This is a result of a large-scale changeover to bulk mining with high productivity mobile equipment, explained Andrey Zvonar, the technical director of Apatite JSC, and this is the field where Scandinavian technology is of decisive importance.
Sandvik and the former Tamrock have been involved with drilling in the Kola Peninsula since 1962, when the Tamrock underground hard rock drill equipment department received its first order for mechanized pneumatic drill equipment. This was for use in the construction of a power plant by the Finnish company Imatran Voima Osakeytiö and led on to the delivery of 100 units. Although it was not until 1977 that the Apatite operation started buying pneumatic self-propelled drills from Tamrock, this too led to greater things: equipment sales and technical communication gradually strengthened, building a relationship that proved valuable for both companies, especially during the Perestroika period of the early 1990s when Russia’s centralized trading system broke down.
During E&MJ’s visit to Kirovsky mine, Alexander Sakharov, head of underground mining operations, took us down ramp to see sub-level caving on the +236 m ASL horizon. While we traveled in one of the mine’s Minca personnel carriers he mentioned that Paus is one of the manufacturers supplying utility vehicles to the mine. Sakharov explained that, when using sublevel caving where the orebody can be 150- to 170-m thick, Apatite JSC mines identical blocks that are typically 140-m wide, 220-m long and 80-m high. The perimeter drifts are sometimes excavated in waste rock but most of the development is done within the orebody. The stopes are mainly 4 x 5 m wide in cross-section, driven at 10- to 15-m intervals, and the ore hardness is typically 16 on the Protodiakonov scale.
Using a seismic monitoring system with predictive capability, the mine’s geomechanics team determines the amount of support necessary, usually in fracture zones with oxidized materials that also let water into the mine. Kirovsky mine has a Sandvik Cabolt rig for cable bolting. Mechanized equipment from Normet in Finland is used to apply 5 to 20 mm of shotcrete where necessary. The mining system at Rasvumchorrsky is much the same.
Kirovsky develops about 22 km of drifts annually using Tamrock Axera and Minimatic rigs as well as Sandvik DD320- 40 machines. Typically 60 holes are drilled to blast each face and the advance rate is 4.5 m per drilling shift on average. To relieve rock pressure either the Axera or Solo rigs are used. These rigs drill a row of holes, spaced about 1.5 hole diameters apart, in either the drift wall or roof. For safety purposes, the mine scales the drift roof using either a Tamrock Scaler, Normet, or other machinery. In total Kirovsky and Rasvumschorrsky have 34 Sandvik face drilling rigs, of which 13 are Axeras and 12 are Minimatics.
Apatite drills production blasting uphole fans using tubes. The fans are 2 m apart with six to seven holes that are 102 mm in diameter on average. The hole depth averages 35 m. Sandvik rods and Mitsubishi bits are mainly used. Charging is done with either Paus or Normet machines using Grammonite M-21 explosive. The two underground mines have 11 Solo production drilling rigs.
Blasted production ore is loaded by a fleet of electric LHDs comprising some 38 Sandvik LH409Es and Toro 400Es, each with a capacity of 10 mt, and two 14-mt payload 1400Es. These LHDs normally tram 150 to 250 m to the nearest ore pass and have been loading and hauling 10 million mt/y ore on average. The mine also has 23 Sandvik diesel LHDs, mainly Toro 007 and LH410M units, primarily used for loading development rock onto eight Sandvik Toro 40 and 35D trucks which haul to the skip hoist. These diesel machines may also be used in production stopes that are a long way from ore passes.
There are rail haulage levels at +322 m and +252 m that deliver the ore to two gyratory crushers that in turn feed a threestage, 1-km-long inclined conveyor hoisting system. This system has two 1,600-mt/h conveyors that began operation in 1975. Another two haulage levels, +410 m and +460 m, deliver ore to a vertical skip hoisting shaft. The rail haulages have a total track length of 90 km. Both the conveyor hoisting system and the skip hoist load ore trains directly. Ore from the open-pit mine on the Yuksporr flank is trucked by 45-mt capacity BelAz vehicles up to a bench above a rail spur, dumped, then dozed by gravity over the edge to the rail track level below, where it is loaded into the wagons by an EKG electric shovel. The conveyors hoist around 8 million mt/y and the skip hoist about 2 million mt/y; the open-pit contributes approximately 1 million mt/y ore.
Since 1977, the company has acquired over 210 Sandvik mobile machines for underground mining. Today, the mobile equipment fleet totals 118 machines and it is going to expand continuously in the future. Maintenance of the underground mobile machines is carried out in two workshops on surface, the more recent of which was built in 2005. Apatite JSC uses a Paus utility vehicle with electric generator to power the electric LHDs when they need to move on surface.
The growth in underground output has been achieved partly by expansion of the machinery fleet, partly through increases in the equipment’s productivity. For example, the average output of the Toro 400E LHDs has been boosted many times, and enhanced Minimatic drilling jumbo capacity has allowed the mines to increase drifting from 620 running meters to 1 km. Apatite JSC plans to complete the changeover to new technology in the very near future.
As well as changing mining method and mechanizing, the company has progressively invested since 1997 in the development of two new mining levels, at +170 m and +90 m, in the Kirovsky mine. The +170 m level will eventually mine both the Kukisvumchorr and Yuksporr flanks of the orebody while the +90 m level will work the Kukisvumchorr flank. Operations started on +170 m during 2002, boosting mine ore output to 11.5 million mt/y. A rail haulage system feeds an underground crushing complex that was commissioned in 2006–2007. Construction of the new Main Shaft 2, which will raise Kirovsky capacity to 14 million mt/y, is on schedule for completion in time for the planned commissioning period in 2012–2013.
Underground mine drainage at Kirovsky is carried out by four catchment tanks and five sets of pumps, with water level monitoring on each stoping level. The mine works four seven hour shifts.
Progress at the Rasvumchorr mine is also making a very important contribution. Operating in difficult conditions within the virtually exhausted upland part of the Apatite Circus orebody, the mine has increased ore output by 2.5 times over the last eight years. This has been achieved by mining reserves in the barrier pillar between the Apatite Circus and Rasvumchorr Plateau orebodies, at the interface with the Central open-pit mine. Construction on Level +310 m, mothballed in 1993, started again in 2001 and was completed in 2002. This year, Apatite JSC plans to complete reconstruction of the transport system on Level +422 m, which will allow output to rise to 3.6 million mt/y by 2010. The implementation of cyclicaland- continuous mining technology will allow the mine to operate reliably at a level of 4.5 million mt annually for sufficiently long to meet the company’s medium term needs. In the future, Rasvumchorrr can be used to access reserves remaining below the Central open-pit.
Surface Mining on the Move
Although production is scheduled to decline and cease, the Central open-pit is still a major operation, excavating 50 million m3/y of which 5 to 5.5 million mt/y is ore. Apatite JSC is still investing in new equipment for this mine but, as Chief Specialist for Surface Mining Alexander Ryzhkov pointed out, as far as open-pit mining is concerned, the company is primarily pinning its hopes on the newer East mine.
This mine incorporates two pits, the larger and longer-run one being Koashva, which currently measures 3.5 х 1.5 km and is up to 160 m in depth. Apatite JSC considers that the design parameters have some adverse effects. There are economic losses during rock haulage (the transfer leg is over 4 km); the volume of waste rock per ton of mined rock is up to 3.4 m3 and is forecast to reach 4 m3 /t in the future; and, as the greatest problem, the water inflow is extremely high because the pit lies in the way of the Vuonemyok River and dozens of creeks. The pit drainage system comprises 12 powerful pumps, a network of pipelines, and dozens of dewatering boreholes. Annually, this system extracts over 45 million m3 water from the pit area. The management and maintenance cost of these facilities is significant. As a result, the ore production cost is much higher than at the Central pit.
To mitigate these disadvantages Apatite JSC decided to make some changes in the Koashva pit. The project included construction of a new crushing and screening plant and an ore transhipment stockyard with rail link, plus reconstruction of the power supply system and hydraulic works. These changes increased open-pit capacity to 4 million mt/y of ore and the plan is to raise it further, to 6 to 7 million mt/y. Meanwhile, intensive follow-up exploration in the vicinity of these open-pits is under way to increase the ore reserve volumes available for mining within the open-pit boundaries. For the same purpose, the company is studying the possibility of increasing the wall slope angles in these open-pits.
Apatite JSC has also invested substantial amounts in new production machinery for openpit mining during the last eight years, both to replace worn-out equipment and to improve production performance. The acquisitions include four Sandvik Driltech rigs for the East mine—one D60KS commissioned in 2000 and a D75KS delivered in 2006, plus one new D75KS due to be commissioned in August 2009 and another that should arrive on site in December 2009. Other additions to date include eight excavators with 10-m3 buckets, including four Terex O&K RH-90 hydraulic units; Russian electric drill rigs and 19 heavy bulldozers from various suppliers. The company has increased its dump truck fleet by 1.5 times to 95 units, of which approximately 50 work at the Central pit. While at some open-pits in the Murmansk Region the mine technology restricts equipment sizes, Apatite JSC has been able to add larger-capacity, 120- to 130-ton models and so boost productivity per unit almost 2.5 times.
Upgrading of two process plants and of the infrastructure of the entire complex is also a part of the phased investment program. By the beginning of 2004 the capacity of the plants was 10.2 million mt/y of apatite concentrate and 1.7 million mt/y of nepheline concentrate. Ongoing improvements are intended first to compensate for the lower grades of ore being processed, so that finished product quality is maintained or improved; second to increase the level of mechanization and process control automation, so that labor efficiency improves; third to reduce power and material consumption and hence the overall cost of processing; and finally to reduce adverse environmental impacts.
The company is replacing worn out, obsolete VL-22 electric locomotives with newer VL-10U units and pioneering a new design of dump car. Scheduled replacement of signaling, centralization and blocking systems (STsB) by car axle counting systems for track vacancy control is under way. A second surface repair facility was recently built at the Kirovsky mine while a similar repair workshop was built at the Rasvumchorr mine in 2002. Apatite JSC has also developed and is successfully implementing a program of efficient power resource utilization, including the installation of telecontrol systems at the Kirovsky mine and extensive modernization, technical upgrading and construction of power supply networks.
Sandvik in Kirovsk
The Sandvik company office in Kirovsk is staffed by three experienced service engineers. Their main task is to carry out service backup of the drilling rigs, LHDs and Sandvik dump trucks at Apatite JSC, as well as at other mines in the Murmansk Region and northwestern Russia. As well as 129 equipment units working for Apatite there are a further 108 Sandvik units elsewhere in the region, 50 of which work for the Kola MMC unit of Norilsk Nickel.
Andrey Kuznetsov, a geologist by education and formerly an Apatite JSC employee for many years, dedicates most of his time to the LHDs and dump trucks; Alexander Zuev concentrates on the underground drilling rigs and Yury Tshelishev specializes in support for the surface rigs and electronic systems.
In general, Apatite has stuck to the strategy set out in the feasibility study. Through the last three years, the reconstruction and technical upgrading work has achieved and maintained tight schedules.
Taking into account recent developments and new factors, Apatite’s professionals have been cooperating with Giproruda JSC as design contractor to define a new long-term development program. This envisages stabilizing the apatite concentrate production level in the period 2015-2020. The in-tention is to secure the ore resource base by developing deeper levels in the Kirovsky and Rasvumchorr mines, by exploiting pit bottom and pit wall reserves in the Central and East mine pits, and through the addition of reserves currently withheld as state reserves. However, some Russian phosphate consumers reportedly argue that these reserves should be made available to other companies to foster competition in the apatite concentrate market.
The PhosAgro group, Acron and Uralchem are the major consumers of Apatite JSC apatite concentrate. Concentrate is also exported to customers in CIS countries, Poland, Finland, Germany, Norway and Belgium. These shipments are primarily dispatched from Apatity via the Oktjabrskaya railway, with the Murmansk section transporting approximately 40%. Approximately the same proportion of Apatite’s shipments is made through the seaport at Murmansk city. While supplying perhaps a third of Russia’s fertilizer material requirements, PhosAgro also plans to take a substantial share of the mineral fertilizer export market: in 2009, the company signed agreements to supply product to two Indian fertilizer manufacturers.