If you want to invest in the mining sector but don't know which shares to buy, then you could turn to exchange-traded funds (ETFs) instead of just buying BHP Group Ltd (ASX: BHP) shares.

That's because there are plenty of ASX ETFs out there that allow you to buy a collection of miners through a single investment. Three that could be worth a closer look are as follows:

ETFS Battery Tech & Lithium ETF (ASX: ACDC)

The first ASX ETF for investors to look at for mining sector exposure is the ETFS Battery Tech & Lithium ETF.

ACDC invests in companies throughout the lithium cycle, including mining, refinement and battery production, cutting across the traditional sector and geographic definitions.

This could be a good place to be for the future as battery technology and lithium are essential to the rise of electric vehicles (EVs), renewable energy storage, and mobile devices. The fund manager, Global X, notes that EVs produce zero direct emissions, meaning broader adoption could result in reduced greenhouse gas emissions and improved urban air quality.

Among its holdings are giants such as Tesla (NASDAQ: TSLA) and Pilbara Minerals Ltd (ASX: PLS).

Betashares Global Uranium ETF (ASX: URNM)

A second ASX ETF that could be a good option for investors looking for mining sector is the Betashares Global Uranium ETF.

It could be a top pick if you believe that nuclear power is the future and another key to the decarbonisation of the planet.

That's because this fund allows you to buy a slice of the leading companies in the global uranium industry. These companies are positioned to benefit over the next decade if the forecast strong demand for the chemical element materialises.

Holdings include locally listed miners Paladin Energy Ltd (ASX: PDN) and Boss Energy Ltd (ASX: BOE).

Betashares Energy Transition Metals ETF (ASX: XMET)

Finally, the Betashares Energy Transition Metals ETF. could be another great way to gain access to the mining sector with an ASX ETF.

It gives investors access to global producers of copper, lithium, nickel, cobalt, graphite, manganese, silver, and rare earth elements. These are all metals that will be important for the decarbonisation of the planet.

Betashares has named it as one to buy. The fund manager notes that "both electric cars and clean energy use notably more metals than their conventional counterparts, and many of these minerals have highly concentrated and insecure supply chains."

Its holdings include Lynas Rare Earths Ltd (ASX: LYC) and Southern Copper Corp (NYSE: SCCO).