LCS for CICO Dahuangshan

Dayhuangshan tuff quarry of Zhejiang communication resources investment Co., LTD. (hereinafter referred to as "Dayhuangshan quarry") is located at the north of Cezi island in Zhoushan. In October 2019, the phase 1 project of 15 million tons/year sand and aggregate production line was fully put into operation. It has also been awarded the "National Green Mine" in 2020, with the comprehensive utilization efficiency of resources up to 100%. As a perfectionist, Dahuangshan quarry made a more ambitious plan to further reduce cost and increase efficiency, improve quality and productivity. 

On-site expert service for equipment failure rate reduction

According to Dahuangshan’s shutdow plan made by Metso Outotec, monthly service is executed by service experts lasting for one week to inspect and evaluate equipment and repair if necessary, in order to reduce equipment failure rates with less maintenance and operational costs. At the same time, the training about equipment operation and maintenance is carried out for onsite worker, as well as safety and special occupation training. For emergency service needs, Metso Outotec experts provide timely remote guidance and can be on site within 24 hours if required. "Our quarry is located in coastal areas, where supply and demand are seasonally dependent and production is volatile, and these services from Metso Outotec provide efficient production of 65,000 tons per day at peak times", said Dahuangshan quarry machinery and material department manager, Ma Yanquan. 

On-site consignment warehouse setup for ensuring parts availbility 

The on-site consignment warehouse is used to store common crusher spare and wear parts. This is to ensure that the parts for planned maintenance can be at their fingertips, and the parts for unexpected shutdown can also be "prepared." To this purpose, Metso Outotec provide professional inventory suggestions according to the actual use of parts combined with maintenance solution after routing inspection, and then arrange delivery in advance to replenish inventory in time. 

Optimization of crushing chamber and liner for improving equipment availability 

Tuff from Dahuangshan quarry is a kind of high abrasive ore, which cases huge consumtions for cruser wears, resulting in high costs for wear parts and labor. It is also a big barrier encountered by Dahuangshan quarry when promoting the work of " reduce cost and increase efficiency ". The large workload of maintenance also increases the security risk virtually. The core of LCS is processes and equipment optimization based on the specific ore properties. 

The earliest problem encountered was the abnormal consumption of Barmac wear parts. Through investigation and research, Metso Outotec engineers guided customers to make appropriate changes to crusher and associated equipment, reducing wears consumption by more than 50%

In the subsequent liner optimization project of the gyratory crusher, Metso Outotec engineers collected partical size of feeding materials, liner wear profile curve and process parameters on site, and gradually promoted the liner optimization by adopting a holistic thinking. After several rounds of optimization, tracking and re-optimization, at present, the gyratory crusher uses the fourth edition of optimized concaves. This includes WX52 and WX65 alloy concaves, which can match with 3 sets of bowl in different specifications. In addition, in the whole optimization process, manganese steel optimization solution and alloy optimization solution are simultaneously carried forward to ensure a smooth transition and stable production operation. 

Production practice has proved that the customized gyratory crusher liners used new alloy material, optimized contour curve design and increased its service life by 4.3 times so that liner replacement can be reduced 3 times. Also, with the pre-assembled spare head, overall replacement time for gyratory crusher is greatly reduced, operation time is effectively improved, and consumption of concaves and packing materials is significantly reduced. In addition, local design and manufacturing has reduced the lead time of alloy liners from the normal 6 - 8 months to 4 months, covering a range of work from data collection, liner design, mould making, manufacturing and delivery. And subsequent repeat orders can be delivered within 60 days.

The cone crusher liner is optimized based on the mineral properties, stress and abrasion area. By improving liner curve and redesigning compression angle, this ensure that its service life is increased by 25%. At the same time, the customized cone feed plate makes the feed plate and liner replaced synchronously, avoiding extra change for feed plate during liner operating and reducing manual operation significantly. "Less liner replacements also avoids the energy, power and labor costs associated with each downtime replacement," Mr Ma added. According to Metso Outotec evaluation, only through liner optimization of the HP400 and HP500 cone crushers, the potential annual total revenue can reach more than 3 million yuan. The annual replacement time can also be reduced by more than 100 hours, effectively minimizing personnel working time and safety risks.

During the optimization process, Metso Outotec will consider the coordination of the entire production system, and propose corrective suggestions for other associated equipment, to ensure that the performance of the entire production line improves simultaneously. Mr. Ma concluded: "After optimization, the frequency of downtime has been reduced and with good equipment operation rate. Now our daily uptime is 20-22 hours, and the processing capacity of the crushing and screening system has been increased from 50,000 tons/day to 60,000 tons/day. In 2021, we are expected to produce 17-18 million tons. In terms of manufactured sand quality, we have reached the National standard II level through technical upgrades."

Achieving better results and creating a better future

As of November 2021, two 800 t/h production lines in Dahuangshan phase II project has also been comissioned successively in May and August. After all lines are put into operation, the annual capacity will be increased by another 7 million tons, exceeding the total designed capacity of 22 million tons.

"One of the main reasons we chose 6 units of Metso Outotec Nordberg® HP500 secondary cone crushers for phase II is easy liner replacement. Moreover, a tertiary cone crusher in Phase I is still in the process of further optimization, which is expected to further release its capacity and reduce the workload. This will help us further achieve our goal of increasing production and reducing costs," Mr Ma said.

When it comes to the future, Manager Ma talked about a series of improvement plans, and presented his unique ideas and insights on the existing problems, solutions, supporting data and implementation progress. In-depth study of the business and positive thinking about the future are the spirit of CICO Staff's tireless pursuit of excellence, which is an indispensable factor for the practice of their aim "building the benchmark of intelligent green mine.”