People in management positions have recently upped their stakes in four ASX mining shares.

Money talks — which is why it can be seen as a vote of confidence when company insiders buy shares in the companies they're involved in. These are the people who are most familiar with the inner workings of the business.

Importantly, they still don't know the company's future. However, people on the board or leadership team make the decisions that shape the future of a business. If they're buying shares, you'd think they are pretty happy with the path they are paving.

Several small-cap mining companies have released change of director's interest notices over the past two weeks.

Not only are these useful signs of belief in the companies, but it's also positive to see greater 'skin in the game' among directors. The more shares a director holds, the more intrinsic motivation to create more wealth for shareholders.

All four ASX mining shares have a market capitalisation of less than $200 million.

Encounter Resources Ltd (ASX: ENR): On 10 April, independent director Philip Crutchfield scooped up 1.8 million shares in the Australian copper and critical minerals explorer. At 22 cents apiece, the off-market trade was worth $396,000. The purchase takes Crutchfield's holdings in this ASX mining share to $2.8 million.

DevEx Resources Ltd (ASX: DEV): Between 10 and 15 April, DevEx Resources chair Tim Goyder acquired 2 million shares through his TRB Goyder Super Fund. Based on the $614,698.68 paid, Goyder purchased the shares at an average of 30.7 cents.

April has been a busy month for Goyder. Additional purchases were made on 9 April and 2 April, totalling another 2 million shares. Goyder's ownership of DevEx is now 17.1% of the company or $21.9 million worth.

Bulletin Resources Ltd (ASX: BNR): Another ASX mining share with insider buying is this lithium and gold explorer. Over 9, 10, and 11 April, director Robert Martin purchased 1.1 million ordinary shares in Bulletin Resources. In addition, 22,858 listed options were added to his name, expiring 30 September 2024.

Martin's purchases were worth $53,220.90, taking his total holding to $3.7 million.

Prospect Resources Ltd (ASX: PSC): The last company with recent insider investments is ASX mining share exploring for copper, lithium, and rare earth elements in Africa. CEO Sam Hosack followed up the acquisition of a Zambian copper project by buying 3.48 million shares between 10 and 15 April.

The shares were purchased at an average price of 14.5 cents per share, amounting to a $503,498.56 investment. After adding to his holdings, Hosack's stake now comes to $2.3 million.