gravel_to_furnace.cs

public void Main(string argument) {

    //get furnaces
    var furnace_list = new List<IMyTerminalBlock>(); 
    var temp_list = new List<IMyTerminalBlock>();
 
    	GridTerminalSystem.GetBlocksOfType<IMyRefinery>(temp_list); 
 
    foreach(IMyTerminalBlock t in temp_list) { 
        if( t.CustomName.Contains("Furnace")) 
            furnace_list.Add(t); 
    }
    //get containers
    var container_list = new List<IMyTerminalBlock>();
    temp_list.Clear();
    
    GridTerminalSystem.GetBlocksOfType<IMyCargoContainer>(temp_list);

    foreach(IMyTerminalBlock t in temp_list){
        if( t.CustomName.Contains("Ingot"))
           container_list.Add(t);
    }

    temp_list.Clear();
    //checks
    if(furnace_list.Count == 0)
        throw new Exception("no furnace found!");
    if(container_list.Count == 0)
        throw new Exception("no container found");
    
    //get inventorys

    var furnace_inventory = new List<IMyInventory>();
    var container_inventory = new List<IMyInventory>();

    foreach(IMyTerminalBlock t in furnace_list){
        furnace_inventory.Add(t.GetInventory(0));
    }
    foreach(IMyTerminalBlock t in container_list){
        container_inventory.Add(t.GetInventory(0));
    }

    //count gravel
    VRage.MyFixedPoint g_count = 0;
    foreach(IMyInventory i in container_inventory){
        var temp_item_list = i.GetItems();

        foreach(IMyInventoryItem t in temp_item_list){
            if(t.Content.SubtypeName.Contains("Stone"))
                g_count += t.Amount;
        }
    }
    g_count -= 80000; //keep 80t
    if (g_count < 0)
        return;
    //move gravel to furnace
    var temp = 1/furnace_inventory.Count;
    g_count *= temp;
    
    foreach(IMyInventory i in container_inventory) {
        var temp_item_list = i.GetItems();
        var index = 0;
        foreach(IMyInventoryItem t in temp_item_list){
            if(t.Content.SubtypeName.Contains("Stone")) {
                foreach(IMyInventory dest in furnace_inventory)
                    i.TransferItemTo(dest,index,null,true,g_count);
            }
            index++;
        }
    }
}