The company owns and operates six quarries, supplying granite, diorite, granodiorite and rohozec stone. Quarrying of stone like this can only be carried out using heavy machinery, and GRANITA Lomy has chosen the Doosan range for these applications, with a fleet of 11 Doosan machines used across the quarries.
The key reasons for choosing the Doosan machines were their performance, economy of operation, reliability and, last but not least, the quality service back-up. All machines were supplied and supported by GARNEA, the authorised dealer for the Doosan range in the Czech Republic. Service is provided by ZTH, GARNEA's contractual partner from Dobrá Voda near Hořice.
GRANITA Lomy decided to buy the first Doosan machines in 2019 when the company bought a large Doosan DL550-5 wheeled loader and a DX380LC-5 crawler excavator. The excavator serves as a hydraulic hammer carrier, and its task is to prepare large pieces of stone for loading using the Doosan wheeled loader. Both machines work in the company's quarry in Chvaletice. The first loader has worked for over 4000 hours and, based on this performance, GRANITA Lomy decided to purchase more Doosan machines. Today, GRANITA Lomy has 11 Doosan machines at its disposal, and these machines are among the most popular in their class.
The Chvaletice quarry is the company's largest operation of its type. It is located between Kolín and Pardubice and has good transport links via Class I and II access roads. This is one of the reasons why stone was quarried here for large projects such as the D35 and D11 motorways. The main type of stone in the Chvaletice quarry is medium-grained biotite granite. Quarrying is done by blasting the rock followed by subsequent stone processing, which is where the five Doosan machines in the quarry take over.
Last year, GRANITA Lomy added another DX380LC-5 excavator and a larger Doosan DX490LC-5 50 tonne excavator for the Chvaletice quarry. Large wheel loaders work in tandem with the excavators, including the DL550-5, the second-largest model in the Doosan range, with an operating weight of over 30 tonnes and a maximum bucket volume of more than 5m3. Supporting the DL550-5 is a Doosan DL420CVT-5, a very economical model, offering significant fuel savings.
"It's a pleasure to work with our latest addition, the larger DX490LC-5 excavator. With a 3m3 bucket, it's a real boost and has made quarrying a much more efficient operation. The power of the excavator and its reliability has been amply demonstrated," says Tomáš Dunda, plant manager at the Chvaletice quarry.
The DL420CVT-5 was purchased for the Chvaletice quarry at the end of 2019, and it has worked for more than 3000 hours. It is equipped with a Continuously Variable Transmission (CVT).
A CVT transmission results from a combination of hydraulic and mechanical technology, providing a smooth and continuous speed variation. The CVT design combines the benefits of hydraulic, mechanical transmission and hydrostatic transmission in the same machine. It allows the DL420CVT-5 to automatically transition from hydrostatic power at low speed to the mechanical system to operate at higher speeds.
The complete driving range, forwards and in reverse, is controlled by the CVT system. Low engine speeds ensure high efficiency and the highest driving comfort irrespective of the traction speed. The power splitting continuously variable technology facilitates moving off softly and hydraulically. Furthermore, with the CVT, a fuel saving of up to 25% is achievable.
"Efficient servicing for all the machines is provided by GARNEA, as part of an extended warranty of 5 years/10,000 hours on all the machines. We are glad that we chose Doosan machines because we can fully rely on them," concludes Dunda.
