The United States Environmental Protection Agency (EPA) e-publishes the definitive volume on how to calculate the quantity of dust from mine (and indeed all) unpaved roads, paved roads, construction sites, and ore stockpiles. Its title is AP 42, Chapter 13: Miscellaneous Sources. Thus if you need to estimate the amount of dust in the air for a new mine Environmental Impact Statement or to compare the benefits of using gravel versus paved roads, this EPA volume provides the equations you should use.

Each section includes a brief description of the physics of the situation, the methodologies to analyze the situation, and most important the equations that give you the means to quantify how much dust your particular operations will cause. This is pretty much what was done in preparation of a paper whose abstract we can read at this link. I quote:

This paper presents PM[10] fugitive dust emission factors for a range of vehicles types and examines the influence of vehicle and wake characteristics on the strength of emissions from an unpaved road. Vertical profile measurements of mass concentration of the passing plumes were carried out using a series of 3 instrumented towers. PM[10] emission fluxes at each tower were calculated from knowledge of the vertical mass concentration profile, the ambient wind speed and direction, and the time the plume took to pass the towers. The emission factors showed a strong linear dependence on speed and vehicle weight. Emission factors (EF = grams of PM[10] emitted per vehicle kilometer traveled) ranged from approximately EF = 0.8 x (km h[-1]) for a light (∼1200 kg) passenger car to EF = 48 x (km h[-1]) for large military vehicles (∼18000 kg). In comparison to emission estimates derived using US EPA AP-42 methods the measured emission factors indicate larger than estimated contributions for speeds generally > 10-20 km h[-1] and for vehicle weights > 3000 kg. The size of a wake created by a vehicle was observed to be dependent on the size of the vehicle, increasing roughly linearly with vehicle height. Injection height of the dust plume is least important to long-range transport of PM[10] under unstable conditions and most important under stable atmospheric conditions.

A good summary powerpoint presentation is at this link. Another superb summary is at Wikipedia

As with all calculations there are caveats associated with the use of these equations, not the least the input parameters and the need for sensitivity analyses. Ultimately it might simply be easier to go into the field, wait for the wind to blow and to observe and measure the dust emissions.

California has a parallel method in the Technical Memorandum California Road Dust Scoping Report. They also have methods for the CEQA process and that delightful document a NEG DEC, i.e., Negative Declaration that in essence says there is nothing to worry about. Ontario, Canada has essentially adopted the EPA approach—but see the details at this link. Utah has a neat worksheet that incorporates the method for quarry and mining operations.