Ivrindi Gold is a new mining and enrichment project in Western Turkey owned by TÜMAD Mining Industry and Trade. With ample resources available, the company wanted to optimize its output by investing in equipment that could deliver a large throughput. Their feasibility study indicated the heap leach process would be suitable for this site and Ivrindi Gold began searching for the right equipment for the job.


In the heap leach process, gold ore is crushed to a -6 mm product size, drum-agglomerated and stacked onto a leach pad, where it is saturated with a leach solution that dissolves the precious metals and carries them to the pad below and on into the ADR plant. This is a cost-effective process, provided the required particle size is reached and the leach solution can access the gold within the product. Otherwise, you risk wasting valuable materials.

We have been very happy with the performance of the F-Series HPGR from FLSmidth. It does exactly what we wanted it to do – it enables cost-effective gold recovery.

Mr. Hasan YücelGeneral Manager of TÜMAD Mining Industry and Trade
Hand-gold-mining-HPGR

High pressure grinding for efficient gold recovery

Ivrindi Gold had commissioned laboratory research that confirmed that a High Pressure Grinding Roll (HPGR) would benefit their process. HPGR technology works by exposing the feed material to very high pressure for a short amount of time. This causes the rock to crack and cleave along the grain boundaries, creating a large number of fines but also forming microcracks in the larger particles. These microcracks create ‘canals’ to the gold ore particles trapped inside the parent rock, allowing the leach solution to access the gold and do its job. The more microcracks and fines produced, the more gold can be recovered. Micro-cracking also increases the leach kinetics which speeds up the gold recovery rate versus conventional crushers.

Choosing a technical partner

Having established the desired technology, Ivrindi Gold began the process of finding the best possible partner. It wasn’t just the HPGR. The contract also included a jaw crusher, cone crusher, screens and other equipment. Ivrindi Gold wanted to work with a supplier who could deliver a full flowsheet solution – and one where all parts performed equally well. This significantly narrowed the field.

 

After looking at proposals from other equipment manufacturers, the decision came down to trust. Who could Ivrindi Gold trust with this project and their future profitability? Having developed a good relationship with our regional team, Ivrindi Gold decided to place their trust in FLSmidth.

 

It may have seemed quite the leap of faith: the biggest HPGR ever built for a gold heap leach operation; the first F-Series HPGR we had ever built, and the only HPGR operating in hard rock mining in the region. But it was a leap the team at Ivrindi Gold were prepared to take because they trusted us to make a success of it. We committed to being onsite throughout plant erection, start-up and commissioning to ensure we wouldn’t let them down.

When is HPGR the right solution?

Not all ores are suitable for HPGR technology and not all ores benefit from crushing to the finer fractions created by the HPGR. In order to identify whether or not your ore and process are a match, you need to undertake extensive lab testing. As with most things, it will likely become a question of cost vs benefits. Does the return on investment outweigh the cost of buying and maintaining additional equipment?

For Ivrindi Gold, lab tests confirmed that HPGR would be advantageous for their materials.

Defining the flowsheet

The compressive force of HPGR enables Ivrindi Gold to achieve the desired product fineness of -6 mm, which would be very difficult to achieve with conventional crushers. With that much of the flowsheet decided on, the rest of the equipment could be determined. In all, FLSmidth supplied:


  • 2.4m x 8.0m apron feeder
  • BRU200/450 vibrating grizzly
  • Primary crusher – TST 1900 Jaw Crusher
  • FLSmidth-Ludowici 3.6 x 7.3 m double-deck screens (qty. 3)
  • Secondary crusher – Raptor 1300 Cone Crusher
  • Tertiary crusher – F3200-W HPGR

 

In addition to the 12 months of site service mentioned above, we also provided training for site personnel. A stock of major wear and spare parts is also kept onsite to ensure the plant is well prepared for any eventuality.

HPGR and plant design details

  • Model: F3200-W HPGR
  • Roll dimensions: 2.2 m dia. x 1.5 m
  • Installed power: 4000 kW (2 x 2000 kW)
  • Ore type: gold ore with high quartz content
  • Design capacity (fresh feed): 1139 tph
  • Feed size: 45 mm x Ø
  • Product size: -6 mm (screen underflow)

Built to last

One of the key advantages of the HPGR, apart from its ability to deliver the fines and microcracks needed to achieve fast, efficient gold recovery, is the high availability compared to traditional crushers.

A compact mineral layer builds up on the studded roller surface, protecting the rolls without affecting performance, and thus extending the wear life of this critical component.

Snowy conditions 

The winter of 2018/2019, when this project was being undertaken, was a white-out. Snowfall made access to the site very challenging, and working conditions even more so. Added to this was the fact that this was the very first – and also the largest – F-Series HPGR we had ever built. The schedule was tight, with no wiggle room built in for development work. And yet the machine was engineered, detailed, manufactured and delivered within the project schedule – a testament to our strong, regional project team headquartered in Ankara, Turkey, and the combined operations and engineering efforts of FLSmidth in Austria and the USA. A key factor in this success is that the frame design of the F-Series lends itself to easier shipping and assembly.


Meanwhile, the site team wouldn’t let a mountain of snow put progress off course. They were able to get the majority of the HPGR assembled on site in about 30 days, in spite of the poor weather conditions.

Running to order

“FLSmidth has been a consistently reliable and dedicated technical partner, not only in terms of the technology supplied but also in the way they prioritized customer service throughout this project and continue to do so with services and spare parts,” says Mr. Hasan Yucel, General Manager of TÜMAD Mining Industry and Trade.


As a direct result of the successful installation and operation of the F3200-W HPGR at Ivrindi Gold, two identical units were sold to a project in Russia in 2020. 

HPGR can be a key part of MissionZero

The growing focus on sustainability is driving new interest in the High Pressure Grinding Roll (HPGR). Using a HPGR as part of a 100% dry comminution circuit will help mines reduce or eliminate water usage where this is possible.

How does the HPGR facilitate this? Well, the HPGR is a dry comminution tool capable of grinding to a very fine (finish) product size. In short, the technology exists to build a dry comminution plant and it increasingly feels like the time to do this is now.

Maybe the answer is to look to the future of dry comminution circuits. Dry classification technology is available now - but dry separation, in most cases, will require a breakthrough in technology. Given this, perhaps the current focus should be on minimising the required water usage and that could mean a focus on dry classification methods.

Dynamic classifiers – for example – produce a steep product curve, reducing the ultra-fines which become problematic during the dewatering process. Removing the ultra-fines should also help with the flotation/recovery process. All this adds up to reduced water usage, or zero water waste, which is one of the aims of FLSmidth’s MissionZero sustainability initiative. 

Contacts

Murat US

Head of Mining - Turkey
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Joe Dziedzina

Global Product Manager - HPGR
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