def get_mineral_resource_flows(fl):
    """
    Subsets the flow list for all mineral resource flows

    :param fl: df in standard flowlist format
    :return: df in standard flowlist format
    """
    flows = fl[fl["Class"]=="Geological"]
    flows = flows[flows["Context"].str.startswith("resource")]
    flows = flows[~flows["Flowable"].str.contains(" ore")]
    flows = flows[flows["Unit"]=="kg"]
    
    return flows