This report examines how the OECD-led global digital tax reforms could lead to lost mining investment and revenue in developing countries if issues related to temporary timing differences are not addressed. This report follows a broader IGF briefing note on the implications for the mining sector of the latest blueprints on global digital tax reforms published by the Organisation for Economic Co-operation and Development (OECD). This report digs deeper into the important issue of temporary timing differences arising under the OECD-led reforms. It examines the impact it may have on investment in the mining sector—particularly in resource-rich developing countries—and identifies possible policy solutions. If left unresolved, temporary timing differences could lead to lost investment and revenue from the mining sector in resource-rich countries, especially in the developing world.