[50] "Some 60,000 Ruhr miners have agreed to work extra shifts--so-called butter-shifts--for the purpose of furnishing coal for export to Denmark hence butter will be exported in return. The butter will benefit the miners in the first place, as they have worked specially to obtain it" (_Kˆlnische Zeitung_, June 11, 1919). [51] What of the prospects of whisky-shifts in England? [52] As early as September, 1919, the Coal Commission had to face the physical impracticability of enforcing the demands of the Treaty, and agreed to modify them as follows:--"Germany shall in the next six months make deliveries corresponding to an annual delivery of 20 million tons as compared with 43 millions as provided in the Peace Treaty. If Germany's total production exceeds the present level of about 108 millions a year, 60 per cent of extra production, up to 128 millions, shall be delivered to the Entente and 50 per cent of any extra beyond that, until the figure provided in the Peace Treaty is reached. If the total production falls below 108 millions the Entente will examine the situation, after hearing Germany, and take account of it." [53] 21,136,265 tons out of a total of 28,607,903 tons. The loss of iron-ore in respect of Upper Silesia is insignificant. The exclusion of the iron and steel of Luxemburg from the German Customs Union is, however, important, especially when this loss is added to that of Alsace-Lorraine. It may be added in passing that Upper Silesia includes 75 per cent of the zinc production of Germany. [54] In April, 1919, the British Ministry of Munitions despatched an expert Commission to examine the conditions of the iron and steel works in Lorraine and the occupied areas of Germany. The Report states that the iron and steel works in Lorraine, and to a lesser extent in the Saar Valley, are dependent on supplies of coal and coke from Westphalia. It is necessary to mix Westphalian coal with Saar coal to obtain a good furnace coke. The entire dependence of all the Lorraine iron and steel works upon Germany for fuel supplies "places them," says the Report, "in a very unenviable position." [55] Arts. 264, 265, 266, and 267. These provisions can only be extended beyond five years by the Council of the League of Nations. [56] Art. 268 (_a_). [57] Art. 268 (_b_) and (_c_). [58] The Grand Duchy is also deneutralized and Germany binds herself to "accept in advance all international arrangements which may be concluded by the Allied and Associated Powers relating to the Grand Duchy" (Art. 40). At the end of September, 1919, a plebiscite was held to determine whether Luxemburg should join the French or the Belgian Customs Union, which decided by a substantial majority in favour of the former. The third alternative of the maintenance of the union with Germany was not left open to the electorate. [59] Art. 269. [60] Art. 270.