When Is the Right Time to Change Your Cone Liners?

Changing cone liners at the right time is crucial to balancing cost efficiency and maintaining productivity. Change too soon, and you don’t get the full value of your liners. Change too late, and you’ll experience significant production losses that cut into your profits. Here’s our advice on finding that sweet spot for liner replacement.

The Common Mistake: Waiting Too Long

From our experience, many operators tend to push liner life too far, trying to maximize usage without realizing how much it impacts production. The optimal time to replace liners depends on how much loss in productivity you’re willing to accept in exchange for a little extra wear on the component.

Condition #1: Planned Replacement

The first key to effective liner management is changing them when planned. Scheduled replacements allow you to have all necessary parts on hand and coordinate any other maintenance tasks during downtime. With potential supply chain challenges, obtaining screen media, manganese, and renting a crane at short notice can be difficult. Proper planning ensures you’re not caught off guard and avoids unexpected downtime.

Condition #2: Avoiding Production Losses

The second key is to change the liner before significant production losses occur. For top-adjust/screw-adjust cones, this is particularly important. As the liner nears the end of its life, the feed size shrinks dramatically, especially in the last third of the liner’s life, which can lead to up to a 30% reduction in feed size. Hydrocones are less affected by this issue since their feed size remains constant throughout the manganese’s lifespan.

Using a belt scale can help you closely monitor production rates and detect when output starts to dip. This data allows you to schedule the liner change at the precise time you reach your threshold.

Setting the Threshold: No More Than 10% Production Decline

So, when exactly should you change your liners? Based on our experience, the maximum acceptable production decline before replacing liners is 10%. Let’s break down why this is important:

Example:

  • Production rate: 200 tons per hour of sellable product
  • Crush margin: $2.50 per ton
  • Production hours per day: 10

A 10% decline in production equates to a loss of $2,000 per day in gross profit. Meanwhile, your fixed costs (such as labour and fuel) remain the same, further eating into your bottom line. Over the course of two weeks, this loss can total $10,000–$12,000, which is enough to purchase at least two new sets of liners. In other words, delaying liner replacement for the sake of “getting every ton” out of the manganese can actually be more costly in the long run.

Addressing Common Concerns

Some may argue that if demand is low and there’s no rush to maximize production, it makes sense to squeeze out every bit of manganese. However, if you delay four liner changes by two weeks each, that’s 44 extra hours of operation added to your season. This additional time translates to another week of wages and fuel costs—expenses that add up.

The Bottom Line: Monitor and Plan

The formula for optimal liner change timing is simple:

  1. Use an accurate belt scale to monitor production rates closely.
  2. Plan your liner change in advance so that you’re prepared with all the necessary parts and resources.
  3. Replace liners no later than a 10% decline in production to avoid costly losses.

Looking for more ways to optimize your crushing and screening operation? Contact us to learn about our innovative equipment and best practices for boosting productivity and profitability.