The modern mining industry in Turkey started with the
foundation of the Turkish republic in 1923. Around half of all
existing natural minerals can be found in Turkey, of which
approximately 60 minerals are economically utilised.
| Loesches vertical mill installation has
allowed Eti Maden to expand its Bigadiç borates
plant by 325,000 tpa. Courtesy Loesche
Turkey is one of the leading producers of barytes, boron
minerals, celestite, chromite, feldspar, limestone, magnesite,
marble, perlite, and pumice. In excess of 150m. tonnes of
industrial minerals were produced, accounting for 2.14% of the
The private sector dominates Turkeys industrial
mineral and metal sectors. Enterprises include exploration and
production companies owned by domestic and foreign
stockholders, mining and manufacturing subsidiaries of large
Turkish conglomerates, and medium-sized family-owned mining
Turkey is the largest producer of boron in the world.
Domestic boron reserves contain about 850m. tonnes of borates,
which means nearly 63% of all worldwide boron deposits are
located in Turkey.
It is estimated that global boron consumption reached 3.7m.
tonnes in 2007. Of this amount, the glass sector (glass fibre,
glass wool, and borosilicate glasses) consumes the most. The
second largest consuming sector is the frit-glaze ceramic
sector, which has also increased significantly over the last
few years (until recently) due to global economic growth.
Borates find use in several different sectors, however the
principal markets are: glass glazes, frits, enamels, flame
retardants, insulation, agriculture, detergents and soaps, and
Colemanite, like other borate minerals, is complex and found
in playa lakes and other evaporite environments. It is a
secondary mineral that is formed by alteration of borax and
ulexite. Colemanite is transparent to translucent and forms
small but richly faceted crystals of milky white or yellowish
Colemanite grinding at Bigadiç
The new Loesche mill LM 19.20 was installed at the
Bigadiç boron works in Balikesir, Turkey in August 2007.
The plant, owned by Eti Maden Isletmeleri, started its
production activities in 1976 and since has expanded operations
to three open pit mines from which 800,000 tpa of ulexite and
colemanite ores are produced.
The raw ore is enriched to produce 650,000 tpa colemanite
and ulexite concentrates and milled into 90,000 tpa ground
In 2004, the company began the expansion of its 650,000 tpa
Bigadiç boron plant with the construction of a third
concentrator that would add 325,000 tpa to the Bigadiç
Milling Bigadiç borates
For Bigadiçs production and throughput
requirements, the Loesche mill LM 19.20 was chosen.
The vertical roller mills possess the following design
features: a flat grinding table, individually mounted rollers,
a hydro-pneumatic spring system, and either two, three, four or
six rollers of conical shape. LM 19.20 has a grinding table
diameter of 1.9 metres and two grinding rollers.
The grinding principle of a vertical roller mill can be
described as follows: the feed material is introduced onto the
rotating grinding table, is crushed by the rollers and ground
through the action of the forces emanating from the hydraulic
roller spring assembly. The grinding material is spun outwards
by the rotation of the grinding table.
The upwardly-directed hot gas current captures the material
in the vicinity of the louvre ring that surrounds the grinding
table and conveys it to the classifier.
Coarse material is rejected by the classifier (according to
the grit size) and falls onto the grinding table again in the
internal grit recirculation system for renewed grinding. On
request, this grit can also be removed directly from the
grinding process to use it as pre-material in other processes
and products. The final ground product passes through the
classifier and exits the Loesche mill with the process gas
No false air intake into the mill occurs due to the complete
covering of the rollers, which also means no dust outlet
occurs. An autogenously hard-facing within the mill provides
The erection of the LM 19.20 started in September 2006 and
the grinding plant was put successfully in operation in August
2007. The achieved operational data of the plant can be seen in
the operational data table.
Operational data of verticle grinder LM
|(% passing 75_m sieve)
||87 ± 5
|(% passing 45_m sieve)
||75 ± 5
Compact VRM introduction
Loesche used the experience acquired in Bigadiç to
respectively develop new concepts for the industrial minerals
sector. To tackle ecological and environmental challenges, the
company has developed compact vertical roller mills: LM 15.2
(table diameter 1.5 metres) and LM 12.2 (table diameter 1.2
With these mills several materials such as lime, quicklime,
dolomite, talc, bentonite, barite and other minerals can be
The design features of these mills (see LM 15.2 3-D
schematic) has some design features which impart the
following advantages: a simplified design and therefore very
robust; can be preassembled in the workshop with the mill
classifier erected onsite site in less than one week (average
time 8-9 weeks); and, a telescopic pedestal arrangement enables
an easier transport on regular flatbed trucks.
In addition the compact modular system for the grinding
plant allows minimum space requirements and the mill enables
the control of particle fineness and size distribution.
The mill is also maintenance friendly and shows a high
flexibility with respect to product changes. In terms of
financial investment, the operational costs are very low; and
the lowest possible investments costs can be guaranteed for a
standard grinding plant.
Not only in the cement or slag grinding industry, but also
in the industrial minerals sector, vertical roller mills show
high energy efficiency and flexibility in respect of different
materials to be ground.
| General flowsheet of the colemanite grinding
plant in Bigadiç with the Loesche mill type LM
19.20 D in green. Courtesy Loesche
Contributors: Dr. Regina Krammer, deputy
head of training center, and Thomas Leppak, head of
customer support, Loesche GmbH, Germany, and Bekir Aslan of Eti
Maden Sletmeleri Genel Müdürlüsü,