Codelco to suspend northern construction projects

Chile’s state-controlled Codelco copper miner said on Saturday it will suspend construction projects in the northern part of the country and try to maintain production at its Chuquicamata mine while staffing the operation with local personnel.

The company issued a statement saying its was taking the measures to guard against the spread of the coronavirus after the government reported an increase in virus-related deaths earlier on Saturday.

Amid an effort to reorganize its much-criticized reporting of virus-related deaths, the government increased its estimated number of fatal cases to more than 7,000 from a previously confirmed 4,265.

The Codelco announcement came hours after the second coronavirus-related death of a Codelco worker was confirmed.

The company said its Chuquicamata mine, where the first coronavirus death occurred early this month, will only operate with personnel from the neighboring town of Calama to slow the spread of the pandemic.

“From now on staffing will come only from Calama,” the statement said, adding that “efforts will be made to maintain production levels at the mine.”

Construction work aimed at completing the Chuquicamata Subterranea project in northern Chile will be suspended as the company tightens its anti-virus measures, the statement said.

Ball Mill Liner Installation Requirements

1. After the mill liner is installed, the end lining plate and the cylinder end cover should be filled with compressive strength grade 43.5MPa cement mortar.
2. The bolts fixing the end liner shall not allow the cement mortar to suffice, but shall be able to rotate or enter and exit.
3. The ball mill lining is generally directional, you must pay attention to it during installation, do not reverse.
4. The arc length of all circumferential slits shall not exceed 310mm, and the excess shall be wedged with steel plates to isolate it.
5. The gap between adjacent liners is not more than 3~9mm.
6. The interlayer should be laid according to the design requirements between the liner and the inner surface of the cylinder. If there is no requirement, the cement mortar with a compressive strength of 42.5MPa can be filled between the two. After the cement mortar has set, tighten the liner bolts again.
7. When installing the liner with rubber pads, open the coiled rubber sheet 3 to 4 weeks before installation to allow it to stretch freely; when using the rubber sheet, the long side of the rubber sheet should follow the axial direction of the cylinder, The short side follows the circumference of the cylinder.
8. Carefully check the liner bolt holes and the geometry of the liner bolts, and carefully clean the flash holes, burrs, and protrusions on the liner bolt holes and the liner bolts so that the bolts can penetrate freely into the required position.
9. The complete set of liner bolts should consist of glaring bolts, dust washers, flat washers, spring washers, and nuts; in order to prevent ash leakage, you must not forget to use dust pads during use.
10. When tightening the lining bolts, a torque wrench should be used for the operation. Lining bolts of different specifications should be tightened according to the corresponding tightening torque requirements.

Ball Mill Liner Installation

1. Before installing the ball mill liners, you should know how many pcs old mill liners need to exchange.
2. Ask an expert to arrange and coordinate the entire replacement process. All exchange need based on work drawings.
3. It is necessary to circulate the remaining pulp in the ball mill as much as possible, remove the rubber pad of the waste liner, clean the protruding point of the wall of the ball mill, and remove dust and descale the cylinder. When cleaning the work, it is necessary to fix the barrel of the ball mill. The workshop needs to have good ventilation conditions and suitable temperature. Then the installer can enter the ball mill barrel to start the operation.
4. When removing the old ball mill liner, first remove the used lining screws, then remove the old ball mill liner one line after one line, and then lift the used ball mill liner. When removing the liner, the person should pay attention to safety and pay attention to the standing position to avoid being injured by the ball mill liner.
5. The new liner of the ball mill should be installed to ensure that the gap during the period is within the required range. Fix the spiral of the ball mill liner. Carefully seal the packing and gasket to prevent leakage of mineral powder. If there is no gasket, it should be wrapped around the corresponding position. Two rounds of cotton cord or hemp plus lead oil. At the same time, it is necessary to apply a layer of cement mortar on the inner wall of the cylinder and screw it tightly before solidification. It should be noted that the thin end of the step liner should be consistent with the direction of the arrow in the direction of rotation of the mill.
6. After the replacement, the ball mill staff needs to confirm that there is no person, no working tools, and other needless things in the cylinder, and it is necessary to carefully check the inside and outside of the cylinder before closing the empty cover.

@Nick Sun       NICK@XZHUAGANG.COM