In afternoon trade, the S&P/ASX 200 Index (ASX: XJO) is on course to record a small decline. At the time of writing, the benchmark index is down 0.1% to 7,801.1 points.

Four ASX shares that are falling more than most today are listed below. Here's why they are dropping:

The 29Metals share price is down 24% to 41 cents. This morning, the copper miner announced the suspension of operations at Capricorn Copper. This follows an extended period of rainfall between late January and mid-March resulting in a steady accumulation of water in regulated structures on site to levels now similar to the levels following the March 2023 extreme weather event.

The Atlas Arteria share price is down 5% to $5.07. This has been driven partly by the toll road company's shares going ex-dividend this morning. Eligible shareholders can now look forward to receiving the company's 20 cents per share interim dividend next month on 8 April.

The IDP Education share price is down 4% to $17.35. This morning, this language testing and student placement company announced the appointment of Kate Koch as its new chief financial officer (CFO). However, due to Koch needing to serve a six-month notice period at Seek Ltd (ASX: SEK), she won't join until the start of October. This means that IDP Education will be operating without an actual CFO for the next six months.

The Mineral Resources share price is down 4% to $66.93. This may have been caused by a broker note out of Morgans this morning. Its analysts have downgraded the mining and mining services company's shares to a hold rating with a $71.00 price target. The broker made the move on valuation grounds following a decent run.