Mining shares are high risk investments especially when they have nothing in the ground. Even if they found something, the next question is the quantity and also the cost of digging it out. Buying these shares just from the hearsay of a friend's friend or some unfounded rumour could mean impulse buying. Greed and impatience play a big role in trustees making such a gamble.

Most mining shares lack liquidity. They are easy to buy. But very difficult to offload. Most have extremely shallow market depth. For example the last trading price of ZZZ shares is $0.05 but the buy and sell spread could be $0.07 to $0.02 respectively. It would be easy to go and buy at $0.07 but if you wanted to sell it quickly, you could be forced to sell at $0.02. This is a loss of ($0.02-$0.07) / $0.07  x 100% = -71.4% !

Mining shares are definitely not for amateur share traders. Even experienced traders should be wary.

There are crooks engaged in PUMP-AND-DUMP sharetrading tactics. They talk up a particular mining share and spread a bit of rumour. Day-traders come in and drive the prices up. Trustees get taken over by greed and buy in. Three or four weeks later the share price plummets 50% to 60%. Massive losses incurred by the SMSF. Some stockbrokers are crooks and encourage CEOs of these small mining companies to release "bad news" announcements that may not be 100% factual just to "short" the shares in the company so that these brokers earn a large profit by shorting the shares. The stock market these days are dominated by BOTs that trade miniscule amounts of shares eg 3, 4 or 7 shares in a company as feelers to gauge where the market is leaning. There is very little trading done by human traders, mum and dad traders. These BOTs are programmed with trigger points to buy or sell shares when the price and volume reaches a certain point. Then with AI, there can be releases of news article in the user's news feed that matches the algorithm of big share trading funds, hedge funds. These fake news can affect the psychology of investors, prompting them to impuilse buy or sell shares. AI driven, targeted stories in users news feed based on their cookies and search history threaten ordinary market forces operating correctly. If users focus on a particular story, the news feed will display more stories with similar characteristics because it predicts that is what users will click and read. The psychological impact causes investors to do things irrationally. In consequence, the market becomes dysfunctional, defies common sense. That is why when investing in shares, one should pick blue chip shares and aim at holding those shares for at least 3-5 years. Market will fluctuate but it will be very expensive of any big hedge fund, share trading group to manipulate in the long run. 

Options and CFD trading in mining shares amplify the losses 10 to 1000 times. Don't even go near options and CFDs. There are Trading platforms/Companies that provide CFD/Options software who trade against their clients! They have the access to the clients' portfolio data, know the contract expiry dates and trade against them. This is highly illegal and unethical but difficult for ASIC to catch. Then you have big financial institutions dealing with Dark Pools and high-speed, low volume trading (High Frequency Trading) that manipulate market prices of ordinary shares. Indirectly affecting the prices of CFDs and options. It's a no-win situation for ordinary share investors like you and me. Stay away from "decaying" investments with expiry dates. Big commodities traders use hedges to stabilise prices of volatile commodities. However, using hedges, options and CFD for investment is a foolish trap.

My advise is to stick to the ASX Top 100 and your fund should do well. Share investment is a medium to long term prospect. Winners are those who can hold their shares for 3 to 5 years.